Is this a good idea???

Ok, hi,. Um, I'm 12 going into 6th grade and I desperately need a cup/regular/padded/whatever u call it bra. I asked how to ask my mom kinda a lot of times just 2 find the rite answer 4 my problem and Im pretty sure I found it. I'm going 2 walk past the bra section when me and my mom r alone and really don't have 2 b in a hurry, and walk into there and say "I need sum of these. How bout this 1?" while holdin a cup(orwatevr u call it) bra. Do u think it's a good idea? It won't b my first bra, I currently wear training bras and lately I feel more exposed and like its not enough. Dou have any ways 2 make it bttr cuz I rlly need it, not just want it. When I measured myself at home and got a big A, small b. And if you're wondering how my mom hasnt notice it probaly cuz I wear really baggy shirts so no 1 makes fun of me. And i have really cute, not really tight but tighter shirts that I want 2 wear. And if I wear tight shorts 2 show her, she won't say anythin cuz I have 4 bros who r always round her and they'll make fun of me. I have sport bras but theyre a small and I'm a large, I mean I guess I could sports bras but don't they make your look really small and then ppl would make fun of me 4 havin small s when I don't. So basically all I want 2 no is if my plan is a good idea. And if u have any suggestions plz feel free to add. I can't tell u the rest of the details cuz I have 2 go. And thx so much!!!!