Is a RM 125 good for me?

Ok, i'm 5'5, 13 years old, 144lbs, and muscular. I am getting a new dirtbike soon, and i'm talking to a guy about a RM 125, and i was wondering if that dirtbike will be good for me, i have experience on Dirtbikes, and i have rode for a while. I have mostly has experience on 4 strokes, but i have only rode one two stroke in my life and that was a Yamaha Blaster, and i can handle it pretty easily. Also, i'm trading for the dirtbike, i'm trading a Weider Pro 9940 Weight Bench, and a 110cc off brand ATV, and i was wondering if its worth the trade? and how much horsepower does a Suzuki RM 125 put out? thanks.