That wait is rather not for the sake of waiting but to have a greater chance to have sex exclusively(children having a chance to live in a full family, partners keeping their health away from getting LTDs unless they got one another way, the feeling of unity sex can give to exclusive partners...)... Marriage is intented to be 'till death tears us apart' (of course life sucks and it doesn't work by many cases), so sex after marriage made sense. Why is there that idea of sex right after the ceremony? Actually, the way I understand this whole concept of sex afrer marriage right after the ceremony is that sex is meant to be a way to marry... not in a legal sense, but in a physical unification sense. Me and my beloved follow this understanding, sex married us, the legal ceremony became just a legalisation which won't change anything by our relationship but will make it some things legally possible (e.g health information if one of us get's into hospital).
Just admit to yourself(just to yourself, not to me): can you forget about sb who had sex with you? Haven't they influenced your emotions no matter how emotionless you flet about them before? Sex is too intimate even if was the most mechanical and uncaring... it always leaves traces, not just physically... And I'm not reffering to my experience but to experience of other, random people I heard of. And also to my lectures on evolution, by humans sex has a function of refreshing and endeepening the bond of the partners (example of sth that differs humans from animals on the sexual aspect; it's also one of the elements speaking for monogamous character of human sexuality, others are e.g: no clear signal from woman's body showing to the male that she is fertile at the moment (so the male has to stay close to his female if he wants her to deliver his offspring and mate with her kinda regularly and often) -in opposite to e.g. dogs, chimpangees; the childhood period and how long the offspring is dependent on the parents. I picked just the biological things here, to not get accused for subjectivism of the provided trait like it would be in case of mentioning love here).
Most of stupid youth actions are caused by the need of fitting in and not feeling 'worse' and well as the stupidity and lack of consciousness and actual understanding of the consequences (it's like with the cigarettes, at least in my country: youth smoke bec. they think it makes them look so adult/mature and others don't want to get accused of being 'kids' by those who smoke, but still they have fun with smoking. Some of course don't care and won't smoke because they don't want or have some common-sense already -or have e.g. asthma- but many get addicted as teens, and later, when they become wiser, they notice how much money these cost, they start to understand it's dangerous to their health etc. but still, part of them won't give up smoking)... sex becomes one of these things... humans have a tendency to try out things most of people around them already tried or say they did... Of course, I agree with you on this partly, because not everybody follows and acquires such approach and behaviours.
Not disagreeing with your reply, just being in some mood of writing at the moment. I think I don't need or even want to write anything more today