Don't pretend I'm stupid, you know I am.

My Aasimar Paladin flexed his wings and flew in the Fire Giant's face.

I was 30ft away from it, with folks in between. Bonus Action to get wings and then I flew at the monster diagonally. DM allowed it because it was the right thing to do but... the giant is 18 to 20 ft tall and that gives us a hypotenuse of more than 30ft, like 34 if 18ft tall. I used more movement than allowed.

So, questions:

I spawn the wings, I'm still on the ground. Flying up or down takes movement. I got fly up first and then move around. As in, fly up 10ft and forward 20ft. Right?

In the first turn I get the wings, I won't be able to advance full 30ft unless I'm just hovering over the ground a bit. I'd need to expend some movement to leap in the air before moving.

I can still walk and then fly, or vice versa as long as either movement doesn't reduce my speed to 0. Am I correct?

If you have any other insights on flying Aasimars or flying speed in general, please share! Thank you!