Chances of getting into a good school?

<p>Hello there, first time poster, longtime lurker here.
Anyways, so I'd like to get into one of the greats- Choates, Deerfield, Thatcher, Andover, Exeter, Lawrenceville, Milton, etc, with Andover and Exeter being my ultimate top two. If I theoretically got into both, I'd most likely go to Andover. At the moment I'm in seventh grade, so I know I don't really need to start thinking about this for another year, but I'm still interested. Boarding school isn't a must for me, so while I do really want to go, if I don't I'll end up at my local public high school. Also, there's a application-only public highschool in my town, but it's super competitive and I don't want to set my heart on it too much. I'm applying for that this year, as it starts in eight grade. It actually works out- Say I don't get in this year, I'll apply for boarding school next year.
My SSATs are decent- I always get 99 in vocab, and while my reading fluctuates a bit, it's always been in the top 90th percentile. The lowest score in reading I've ever gotten is a 94, and 99 is the highest. Math is different. At the moment,I'm barely pulling 80s. I haven't gotten my latest score back yet, so it could change, but the highest I've ever gotten is 81. Sad, I know, and I'm worried it's going to keep me out of the schools I want to go to. However, I've been studying hard, and I really think I'm going to do better on this one.
As far as EC's go, I'm not brilliant. I've been playing trombone in the school band since fifth grade, jazz band since sixth, the first year they were both offered. Science Olympiad this year, and hopefully next. I'm also in debate club, and we don't have a team but will next year, which I'm trying out for. Also, there's national junior honors society, and I was in student council last year and hopefully will be next year. In solo and ensemble contest for music, last year I got a district one, which is the best possible score. I also did the same for drama speech contest this year, which I wasn't in last year. Music solo and ensemble isn't until February. I'm also stage crew for the musicals, and will be trying out for club soccer for the first time next year.
I'm a good student, all A's, and teachers generally really like me, so reccamendations shouldn't be much of a problem. I'm a very strong writer, but have entered no contests. Mainly since there aren't any.
I interview well. I'm fairly outgoing. I'm trying not to get too attached, since looking around these boards I see people who have much more impressive things under their belt, but I would love to go to Andover or Exeter, or any impressive boarding school really. I'm a Caucasian girl. I'll also be applying for some serous FA- not full, but I'd probably only go if I only had to pay 10,000 or less.
Anyone willing to chance me?</p>