Sex???

So I know this guy from high school but after we graduate he went into the army and I stayed behind and got a job. Went in high school we were just friends but we always liked each other he texted me this month and told me that really likes me And I like him too and we are the same age (18) well so our conversation moved into sexting and he want me to have sex with him went he gets back from training ...... Should I or shouldn't I say yes???? Plz help!!