Hey man, good call - you'll look good with the buzz.
On moms, there's a lot going on there, so don't worry too much about it. Yeah, there's probably a little hangup on old stereotypes. They also instinctively have a hard time letting go of their little boy, which this ties into.
She also might just be trying to help - she probably knows you're not loving losing your hair, and is in some way trying to reassure you that you don't look bad as is. When I was 17 and it started for me, I freaked and went to my mom and said, "I think I'm losing my hair!!!" For awhile, she'd assure me that I had the same amount of hair as the day I was born. A year or so later when it started to be clear that wasn't the case, she tried helping me find all kinds of ways to get it to stop. Probably not what I needed, but she didn't know any better! Cut her some slack, and she'll get used to it!