I started to build a family tree with myself as level one. I then branch to my father and mother, then their parents and so on and so on. Should I have split the tree into maternal and paternal trees? Also my father changed his name (Americanized it) before I was born so my tree name is the American name not the original Polish one. Should I have used the original name?

I would keep your tree as is, especially if you are starting from you. I did have two trees at first, and just recently put them together.

As for the name, you can pick which ever you wish. I would however at least note somewhere about the name change, there should be an AKA or alternate name fact you can use.

Thanks!!

My tree starts with me and includes multiple marriages, divorces, adoptions, etc for both my mother's and father's sides. I have 2,488 individuals.

The more - the merrier!

Regarding the name, personally, I would use his original name and then add a AKA fact with the American-ized Name... Since we enter females with their maiden name, I think adding you father's original name makes sense.

Thanks!