I just planted a red sunset maple and, while the bottom 2 feet of its
trunk is perfectly straight, the remaining trunk (10 or so feet) is
leaning somewhat. There is a crook or knot (or whatever you call
it--it almost looks like a swollen finger joint) in the trunk where it
begins to lean. Is is better to have the bottom part of the trunk
straight and let the top portion lean, or is it better to lean the
bottom so that the top part is straight (since the trunk is bent,
there is no way to make whole thing perfectly straight)? Also, would
it be too late to fix if I need to (the tree has been in the ground
for about 3 weeks now)? Finally, is it possible that this will all
even out as the tree grows and the trunk thickens?

This is the first tree I've ever planted (so I have no idea what I am
doing) and it's going to be the centerpiece in front of my house, so I
want it to look good. Thanks in advance for any advice!

Brian