Personally if I were you I would be getting a 125 2t. Your about the smallest height I would recommend for that bike, but your weight is about right for the bike. You will grow into it, if you got anything smaller you will be mad next summer.
Just take it easy an cautious your first few rides. It literally takes 1 second of throttle at the wrong time / spot to send the bike + you into a tree,rock, outer space, etc.
Aggressive on a ttr125 compared to on a yz125 is the same as aggressive in a Volkswagen beetle compared to a new corvette.
But once you get used to it, you'll ask yourself how you ever rode the ttr :)