Not too bad for your first build. Not the best choice of wood, not the cleanest cuts...but at least you had a plan, knew the size of the box, and knew what and how to tune it. Just make sure you seal it up real good and you should be OK with lower wattage.
Most people first box, that I saw back in the day, were usually made of plywood as well. Really thin plywood. LOL, I remember some friends had a "ported" box where they just drilled different sized diameter holes in the box.
Not too bad though...and at least you learned some stuff...your next box will be better!