It looks as if it could be an M. acuminata. Leaves are right...hard to tell w/out the shape of the mature tree. That is some specimen for only 3 yrs! WOW! I've grown a couple of species from seed (M. fraseri and M. virginicus)...they're in their second yr and they are about 4 inches tall! How did you do that?

Looks similar to Persimmon as well if you planted that. Looking at the leaf buds in winter would help distinguish.

adidas : Haha, thank you! I am actaully in 6a (where this plant is located) at the moment, but it was planted in late-November of 2011 and began growing the following spring. So 3.25 years to be exact. It was also planted by a south-facing window with lots of rocks merely inches away. Lots of warmth. It will have to be relocated one day in the near future...

esh_ga : Thanks for the other tip off for Persimmon as that was another one of the seeds that I had planted in that given location. I will make sure to check the buds if I am still at this locale come budding time.