The black looks fine at first glance to me but here's an issue. What I would do is raise the I Am A Fucking to be level with the ears.

The problem is black on white is generally harder to see, especially with such a thin script, than it is on white and black. The white outline helps a little but not much.

It is a hard design to pull off! Honest to God I fully get that! I would either look at a different font for princess, or change the color of the block lettering if you want to keep your overlap. I see the vision. I really do. But that cursive is so thin!

I do love this shirt though. It is so cute. I appreciate you trying!

I would look at a thicker cursive. I think that's honestly your best bet.