Hello, I am new to this forum, so apologies for the long post. I am a new stepmother, although I bring to the marriage a child (daughter, age 5) of my own. While generally I am okay with my new husband's kids, I am really struggling with my feelings about his stepdaughter, J, age 12, and her developmental disabilities, both physical and emotional.

J is a bright, cheerful, sweet 12-year-old. At least, that's what her birth certificate says. She experienced slow growth early in childhood and hasn't grown at all in the last three years. Her body does not carry even the slightest hint of imminent puberty - no breast tissue, no hair under her arms, no nothing. She is only two dress sizes larger than my five-year-old, and my five-year-old is quickly gaining on her. My husband says her pediatrician has assured her parents that she'll just magically grow out of it and bloom one day, but the fact that she has not grown at all in the last three years seems like a red flag to me that her body may not be producing growth hormone normally. We're discussing options for getting a second opinion or taking her to an endocrinologist, but even if they start her on growth hormone tomorrow, it will take years for her to catch up with her peers.

Whether as a result of her lack of growth or some other undiagnosed issue, she also does not display the personal traits and characteristics that one would normally expect of a 12-year-old. Particularly, she is miles behind her peers in the areas of social development, independence and self-sufficiency. She does not have friends that she calls and texts, nor does she have or get invited to sleep-overs. When given the choice, she prefers playmates who are 7-8 years old, rather than girls close to her own chronological age. She still engages in more "imaginative" or "role-playing" play than I would expect of a kid her age. She is also extremely naive for a 12-year-old. For example, before Christmas I thought I was doing the right thing - enlisting her help and making her feel like a big sister - by making a point of asking her nicely to help me keep Santa Claus fun for my 5-year-old by not letting on that "Santa" is actually me and my husband. Unfortunately, this was new information for J, and she cried hysterically for almost an hour and told her dad that I was an "evil grinch."

I want so very much to like J and have a good relationship with her. But I don't really know what to do with her. On the one hand, I don't want to treat her like she's an 8-year-old (which is what she looks like), because I don't think that's helpful to her in terms of her development. She's in seventh grade, and treating her like a third-grader seems wrong. On the other hand, I have learned that I can't assume that she will think and react to things like I would expect a 12-year-old to think and react to them. Because she is not cognitively impaired - she's actually very good in school and is a fast learner - she sees the privileges that other girls her age have and wants to have them, too. But she's so not ready to have them in terms of her own social and psychological development, that there's a lot of tension in the house at times around the issues. For example, she wants to be able to stay home alone on teacher work days and when she tracks out of school. But she can't even walk around the block of our neighborhood without asking her dad or I to come with her because she's uncomfortable going more than a couple of houses down on her own. When we took the kids to the State Fair, J insisted on holding her dad's hand the whole time and stayed glued to his side, and wouldn't try any rides or games without him being right next to her. I don't think letting her stay home alone is a good idea until she can become more comfortable being independent in other situations, but my husband just wants to not have to hire a babysitter every time he leaves the house anymore.

To make my relationship with her even harder, J displays many of the most annoying personality traits of her mother - she's emotionally fragile, lacks any ability to self-motivate, and generally always acts the "helpless victim." Her mother is the kind of woman who single-handedly moves the feminist movement back a century or so just by breathing - she can't (or won't) do anything for herself, and daily challenges are just "too hard" for her to deal with, so someone else has to pay her property tax bill or get her hot water heater fixed, etc. I don't want to see J grow into a woman who always needs some man to come rescue her and make all of her decisions for her, who repeatedly says "I can't" every time she is challenged in life. So, after talking the issue over with my husband, he has agreed with me that we need to make a point of challenging J to take on age-appropriate responsibility and challenges that will increase her confidence and abilities. Example: When J brought her Girl Scout Cookie form home recently, and wanted us to take her everywhere to sell cookies, we encouraged her to go door-to-door all up and down our street by herself (we have a great neighborhood, so no worries about her safety), in the neighboring cul-de-sac, and around the block. She refused to go more than two doors down on either side of our house, and claimed that it just didn't "feel right" for her to go further without her dad with her.

I don't want to be the "wicked stepmother" who makes her do things that scare her or that she thinks are out of her range, but I also don't want to see her end up like her mother, who relies on her parents, brother-in-law, and her boyfriend for financial support and to do everything for her. Any idea how to challenge J and get her to increase her abilities in the social arena (i.e., make some age-appropriate friends), and to get her to exhibit increased independence and responsibility, without her coming to hate me for it?