Possibly Mimosa Tree (Albizia julibrissin)

Hi Sue, how can you tell the difference between Mimosa and Acacia or are they the same? Can they also be confused with Jacaranda? I will upload an additional photo of a seedling, these are popping up like weeds in my yard, not sure what they are or from where they came.

With so many popping up, there has to be a tree nearby. Can you look around your neighborhood and see what's there?

I don't know tress that well but it doesn't look like a Jacaranda

Looks different from most acacia I have seen photos of.
Mimosa trees readily reseed so I bet that's it.

I agree: Mimosa tree!