Say college. C-o-l-l-e-g-e.
It does not imply you go to a 2 year program. No one in top 20 programs refer to their program as a "uni." They say college.
"I go to college."
"When I was in college..."
"I am a college student."
Now get with it
And there are plenty of third tier 4
year programs that are "universities." So saying "uni" does not mean anything, and instead reveals to the rest of the world you've probably gone to a no-name
program or care too much about what others think of you.
*Saying university should only be with the full name of the program. Like Princeton
University. Otherwise, it's almost always college. And never, ever "uni."