I mean.. It's a tale as old as time. Teens fuck.
Definitely issues between 17/18 & 13 but two 14 yo? ๐คทโโ๏ธ
At some point, if they want to, they'll find a way. I don't know what you can do without being totalitarian and constant monitoring besides teach consent.
Edit: As a caveat, I just realized there are 2 pics and only the 2nd loaded for me, so I may chat ve my answer on revisiting.