I don't have a step family member situation, so I can't help in that regards, but I can help with the attitude problem and i don't think it is so much an age thing as it is a respect thing. We teach people how to treat us and I tend to let things slide with my kids and mine are only 4 & 5!! my daughter has acted the way your is and I tried all kinds of things, but since she was 4, i just couldn't let it continue or hope it would change. i totally altered her environment and our relationship all in one afternoon and it stayed that way for 3-4 months!! First i sat her down and told her that her disrespect was going to stop. i explained that i wasn't going to sit and try and figure out why she was being disrespectful, but what i was going to do was clean our slate and that meant life as we both knew it was ending and we were starting over. I explained that from this day forward my main goal was to teach her manners and respect. I cleaned out her room. I left her with a mattress, blanket, clothes for a week, and her sleeping partner, Belle. That was it. Everything else I packed up except for 5 toys she played with pretty regularly and those I put on a shelf. I went over manners with her and explained from now on, she had to ask politely to play with a toy and depending on her attitude for the day, she would get to, or not. I then made a list of her chores and put little pictures beside so she could remember what they were and i explained that I had allowed her to just get everything and this made her ungrateful and that from now on, she would know what it is to earn something. i explained that as she got thru a week and I could see we were making progress, then she would get to go "shopping" and she would earn a chance to pick a toy to keep in her room that she could play with without asking permission first. Well, let me tell you. We had fits and crying and I stuck to my guns. My daughter does not have that attitude any longer. I'm not gonna say it was easy, it wasn't, she felt like i would give in, but by month 3 she knew I was in it for the long haul and lots of progress occured during that last month. She knew her birthday was coming up and I had discussed with her that I would let her play with her gifts that day, but they would be confiscated until she earned them! Well, amazingly enough she got through one week, then two, then three ... I no longer had to nag her to pick up her dirty clothes or put her plate away or hang her back pack up. I made the mistake of treating her as though she was too young to do these things on her own accord and she met my expectation. I changed my expectations and she changed too. she is much happier, more self confident, more independant, and more loving and much more polite. She remembers that time very vividly as she will talk about it and while on vacation a large child say 2-3rd grade was throwing a very loud temper tantrum and my daughter leaned over to me an whispered, " she's too old for that Mom, i think she needs a clean slate!" I almost choked on my food, I was laughing so hard. So, not telling you what to do, but perhaps the step dad truly loves you all and his advice, as hard as it is to hear, maybe just from him having a bit of perspective. My husband is the one who told me to snap out of it and I guess that plus her attitude that day, just made me snap and see the truth in his words. I know what I did was drastic and I felt that a huge change would make the transition quicker as I didn't want to have to go through this process for months or years before I saw results, that was my choice. I decided that parenting isn't easy and I wanted to prepare her for the world and she just wasn't getting that the way I was doing it before. Once she got her things back, I used her items as currency. she broke rules, she paid a fine, just like we do in the real world. i have her go with me to donate her 'fines" to charity. This works good all around, cause charity gets some pretty nice things, they always pick toys that are cheap, or things they don't particularly care for, so I don't have to deal with huge piles of unused toys, and they learn quickly that their choices have consequences. i'm proud of both my kids and their manners and while they still are kids and get crazy sometimes, they truly are appreciative of things they get and spending time with us. So, simplify her life a bit and she'll fight you for awhile, but then she will respect you for standing up to her and letting her know that her Mom respects herself more than that and she will respect you too. Remember, you can't demand it, but you can command it!! Hope this helps you. Best of luck.