Do I have to wait to level 3 to choose bladesinging?

I do not the availability of the class from the start, so im assuming its

wizard-- then at level 4 choose bladesinging specialization?

Just wanted to make sure i have the whole mod thing set up correctly.

I have BG3 mod manager
-- DLd and installed :

Expansion Bladesinger
5e Spells

moved those 2 into the mod manager, and saved mod manager setting.


thanks for any info