Going to look at a horse tomorrow (first time buyer)!?

[Jollywilderness798]

Tomorrow I'm going to look at a horse I found online (it was an ad on a facebook page of somebody's OTTB & OTQH rescue). She's a 4 (coming 5) yr old, 15.3hh, OTTB mare. She is UTD on everything, has no vices, and was last raced in April. But she is said to be "Super sweet, super broke, dead quiet girl. Novice friendly, great on trails and in arena." And this lady seem very genuine. Now I know you're not supposed to trust anybody's opinion but worst case scenario, I go home empty handed. If so, I'll keep looking. But I'd really like to see this mare (: This will be my first visit, if I like her I'll come back with a vet, my trainer, and a trailer. I'm just nervous, I've never went horse shopping before! How do I know this is the horse for me? How do I know if she likes me? And also, will I be too big for this mare? I generally like smaller horses even though I ride English, I just find them more comfortable. But I am 5'4" and 115-120 llbs. I am 14 but I won't grow anymore, and if I do, it'll be no more than an inch. In lessons I ride 14.2hh and 16.2hh mares. I feel best on the shorter mare but it doesn't look as good. Thanks!!
Blujay- Fully aware it could be a sham, I doubt it but maybe! I didn't ask for your input on *that* though. She IS young, I realize. But that's what me and my trainer want and she could be one of those rare young horses that are quiet and broke.
She's normally ridden in a halter but can be ridden in a snaffle, too. I know those questions, as well. I'd never get on a new horse without seeing it being ridden before hand. (:
Karen- Um..I'm not a beginner. My trainer was going to have me buy a green horse. I don't want some tiny QH. I do eventing, that just would not work. I didn't ask if this horse was right for me, so why I'm getting such answers boggles my mind.
And she is not lame, she was just too slow. She only had 5 starts. I won't be boarding at my trainer's place..because she doesn't have a boarding facility..
And she's free...