later or after?

[fire fly]

Around the age of sixteen, you must make one of the biggest decision of your life. “Do I stay on at school and hopefully go on to university _______________?

The answer is “later” Why not “after? Thanks.

[Raymott]

Around the age of sixteen, you must make one of the biggest decision of your life. “Do I stay on at school and hopefully go on to university _______________?

The answer is “later” Why not “after? Thanks.

"after" isn't wrong, but "later" is more common and more colloquial.
With "after" you'd normally say something like:
“Do I stay on at school and hopefully go on to university after that/after I matriculate". "Later" sounds better if you have to choose just one word.

[David L.]

Because 'after' is a preposition, not an adverb. Prepositions go with nouns.

'later' is an adverb modifying the verb 'go'.