Mom and girl problems! Please help me!?

So to start off I'm just going to say that my mom and I are kinda like really good friends. The only thing is that I have a hard time telling her stuff. For example I didn't get a bra until I was 13 and I really needed one then but I couldn't just talk to her about it I had to right her a note I was so worried and nervous about what would happen when she found the note in her purse that I almost threw up! And then on the topic of shaving. I was so embarrassed that I was 13 years old and I didn't shave that everytime I took a shower I went into the cupboard and used one of my moms unused razors. Eventually I just decided to take one of her razors and put it in the little bag i put my body wash and stuff in so I could use " my own " razor. But back on the topic of bras. Me and my mom and my brother are going on a week long trip next week. I realized that I needed some more shorts and stuff for the trip so I went on line and was shopping and then I thought " oh man I'm gonna need more than just the 3 bras my mom bought for me when i got my first bra" so I went to target.com and bought like five more bras so I would have enough for our trip. Well the package came today and I went in my room and opened the box I hung up the two shirts and two shorts I also bought and then turned my attention to the bras. I tried them on and they all fit me. But I didn't want to tell my mom about me buying more bras I don't know why I'm so worried but she Just is so critical about everything and I never te her anything about school or m friends or boys and she never asks either she just assumes that I'm this perfect daughter she's always dreamed about and everytime I'm "me" around her she gives me this look like I'm being ridiculous and stupid so I go back to the " me " I am when she's around and I hate havin to be two people. I love my mom with all of my heart but sometimes I can't function around her. So I guess I'm just asking what to do about the bras and shaving and her.