I'm sure I could've taken lunch from home if I wanted.
We had food at home, like you describe. But there were a couple of things working against me.
1 - I wasn't going to get up and ready for school any earlier than I had to. And since I had to walk just under a mile to get there, I had to account for that time. So I didn't leave myself much time to pack a lunch in the morning.
2 - Perhaps a bigger issue - I was a pretty introverted and self-conscious teen. And, let's be honest, Jr. High sucks as far as kids worrying about peers and fitting in. So I didn't want to draw attention to myself by sitting down to lunch with friends who all had a hot lunch while I had a sack lunch from home. Weird? Looking back, definitely. But enough of an issue that I didn't pack a lunch.
I survived. It's OK. And I learned a lot about finances having to manage stuff for myself - which was also a good thing.