bra size help

Nicole • I'm 17
Where do u ladys buy ur bra.. now I'm only 16 and about a year which I got check I was 38DD now... I got check this Year in beginning of march im a 34 DDD WHERE THE HELL DO I BUY BRAS. 
I can't find anywhere so 
If u lady's and girls know anyplace or app idc 
Plz plz tell me