Out of those 3 options I would go with the emilia, simply because I think they are one of the best looking T's out there, although you really can't go wrong with any brachypelma.

Like John said, I'd suggest getting a spider that is at least 2 inches because they are much more hardy and forgiving to human error than a 2nd instar, especially since it's going to be your first T.

I have both an emilia and a smithi who have been kept in the same conditions for the past 6 mos and the difference in growth rate is remarkable (the smithi is pushing 3 in and the emilia is barely an inch), but every spider will grow at it's own rate.

I say you just get all 3, it'll happen in the future anyways haha. Tarantula's are addicting.