I think the manga is a lot lighter on the scenes and doesn't specifically include the "act" but if it makes you uncomfortable it's probably a good idea not to read it? Honestly, you're old enough to make the decision for yourself to read it. But uh, maybe avoid the novel if you already feel like you're doing something you shouldn't lol
Umm, you are already 16. You shouldn't read it if you are uncomfortable but most teenagers read stuff even more adult rated than this. This is just a romance story with some implications about the acts. There is nothing weird about it. Trust me, I used to read some really f*cked up shit when I was 10 (I still like messed up things but not as bad as what I used to read) ( ̄∇ ̄")
Iam only 16