There is a whole lot of difference between 7 and 8, you may be really surprised.

8 is when DD and pretty much her whole 3rd grade class really changed. They quit looking like really little kids, and they do act different. (Although I will say it could be a personality thing because my Dad was always a wanderer -or as he would have said- explorer- which used to drive my mother CRAZY on vacations and when we were out somewhere before cell phones, because we lost him a lot when he got bored with what we were doing and wandered off to see what else was around and we spent a lot of time trying to track him down.)
DD(10) chickened out at TOT when she was 8. A CM offered to walk her down to the area near the ride exit and even to stay with her for a few minutes until we got there. I knew she was scared in the building and I also had been down the chicken exit at TOT before, so I knew she would have stayed scared, so I just let DH ride and went with her. I wasn't comfortable with leaving her on that one. However, she also chickened out at the ride vehicles at Expedition Everest and that time we sent her to the gift shop and DH and I rode it. We knew it was just going to be a couple of minutes since we were getting on the ride right then. Also at that age with the tiers at EPCOT and the wait times at RSR at DLR, we started utilizing the single rider line for TT and RSR quite a bit. At first I was a little nervous, about having her ride by herself and then wait at the end if she got off first, but she was great with it. I would have been okay sending her to the gift shop at RNRC if she chickened out as we were getting on the ride (she won't even get in line for that one, but she did ride EE last trip). My only fear is that a ride could get stuck with DH and I on it, and her waiting- we are sure that she is prepared that is always a small possibility and that she should stay put right where we told her to be and that she can always go talk to a CM behind the counter.