When They Found Out I Was Reading Their Texts...

So my kids have this group chat with all their friends, and sometimes they'll post these hilarious memes or just talk about their day. I was supposed to be checking in on them but instead...I ended up reading over some of the texts between them. I know it's not right, but there were times when they seemed so stressed out that I wanted to help. And let me tell you...there are some things a parent needs to know! But then again, they're growing up and deserve their privacy too.... Should I just talk to them about this or what? Am I overreacting?