i think i might be stupid

I was catching up with an old friend yesterday, because I've been dealing with dark thoughts. So to help distract me, she decided to teach me algabra (shes studying at a college level, but she taught me the basic version).

I was always terrible at school, so I never managed to understand how algabra worked. But after she spent a few hours showing me, i finally understood, and I felt kind of good about it. I knew it wasn't impressive, but idk, it feels good to know stuff

Then i mentioned it to another friend, and he pointed out that this math is meant for 4th graders. He said I should be embarassed that it took me until age 20 to learn it, and I should especially be ashamed that I struggled ao much when learning it yesterday

That kind of hurt my feelings. I know deep down that I should have learned this long ago, but idk. Was he right that I should be ashamed? Am I stupid?