Feeling a bit down

I know this is petty and probably should be the least of my worries but it’s getting to me. I’m 24 weeks pregnant and I’ve noticed some stretch marks coming in and it’s been upsetting me. I’m happy my baby is growing and healthy I just didn’t think I was gonna get them this soon or at all. I’ve been moping around the house which upsets my bf because he thinks I’m being a big baby ( probably am) and he tells me there’s nothing wrong with them and to get over it. It’s hard seeing your body go through changes ( unflattering changed at that) I don’t know I guess I just wanted to rant a little bit.