I had to go to a black tie event at 2 weeks PO so I had to buy a bra as I couldn’t wear my macom/sportbra underneath
I just bought an un padded t shirt bra and cut out the wires underneath – i tried on a C & a D and there was no way the C was fitting, so it was the D.
Lol so I measured myself.
I don’t see what harm it does if you want to go and try a few bras on to see what sizes you’re fitting in right now.
As long as you know that it might change with D&F.