Congrats! That's so exciting! Hope it goes well when you see her, and be sure to post pictures!
Yours is really an example of why we should ask for things we want, because you never know where it might lead.
One word of caution, the arrangement you're looking at is not typical (with him buying the horse for you). Make sure you get your agreements in writing. As nice as everyone seems, you don't know him that well yet, and there are too many areas things could potentially go wrong. Protect yourself with a contract.
Some things to think about: what if the horse gets injured (or worse, killed) after he pays for the horse, but before you pay him? Who is paying board, feed, farrier, vet, wormer, etc? Are there any specific living arrangements (e.g. Does the horse have to remain on his property, or will you take it elsewhere)?