Well, i'm 18 and i dont reckon any of my friends that are engaged or Married (forget about kids :|) I think an early engagement isn't a big issue , if you think that they're the one and you feel strong devotion to them then you can think about engagement, but getting married at such early age, for god sake you just came outta teenhood, Plus most of such marriages end up is a mess, after a few years you might think all of this was a mistake and then you realize you already got a kid and it becomes difficult to separate too.
My POV, take it easy, take it slow, don't end up doing something that might make you feel guilty or regretful later on in life.
I don't think most of the people who get married at this age can actually afford to have a family, You've not completed your education, you don't have a full time job, so i really wonder why people do it so early.
You decision is totally correct and i support it

Don't let anyone pressurise you into something you might not be ready for
EDIT: Oh i guess i got a friend who got engaged at an early age ( ͡° ͜ʖ ͡°) His name is P3IN, the same dude who liked this post ( ͡° ͜ʖ ͡°) Apparently he thinks it was a good decision and he's good with it ( ͡° ͜ʖ ͡°)