It’s doable, but you need to be able to realize that peer pressure is just pressure and not something you’re actually supposed to comply with. You also need a girlfriend/boyfriend who will not put that kind of pressure on you, obviously. That kind of pressure is still resistible, but it exposes you to powerful temptation to rationalize and justify something (in this case ‘something’ is fornication) you don’t even actually want to do.
Not a smart move, yes, because discernment is necessary, but the thing is: marriage is not a crowning achievement for having found your soulmate or some other other half magically separated at birth etc.

Marriage is only the beginning of the path. And no, I somehow doubt that people are supposed to marry only in their middle age and only after 5 or so years of Tolkienesque courtship. Marriage is not the zen of attaning enlightenment together and moving on to a higher plane of spiritual existence intended for those who know (it’s easy to extrapolate that kind of view into a gnostic heresy).
Look at canon law. I know it’s not a work of theology, but as far as I go it drives home the message that after puberty + more or less sound catechesis one should be good to go.
Again, marriage is not a higher plane of existence for M.A. holders in theology with an accomplished internship in a contemplative monastery. It’s something a not particularly retarted adolescent should be able to pull off by default.
And the rest is hard, hard work. The part that everybody dreads and some don’t even think about. Including a 16 year old boy who grew up on a farm and didn’t ever go to school, like it used to be.