I took the DLAB today and got a 99. I’m interested in 35M, but I’m torn between enlisting or doing ROTC in college first. Suggestions/tips?

A 99 in your DLAB is not a stellar score. You would either receive a very low level language or need a waiver for a language. That puts you at a really high risk for failing language school.
As for enlistment vs commissioning, that's a very personal choice in my experience. They're very different roles, almost like the difference between doctors and nurses. Both great jobs, just very different career tracks and roles.

Justin,
You will likely get a myriad of answers to this question and ultimately you will decide on your own which of them is right for you.
I was faced with the same question and tackled it in my junior year of high school by enlisting in the delayed entry program. The year was 1968.
I wanted the Infantry with the goal of being a Drill Sergeant, then to head off to OCS or Army ROTC.
Upon accomplishing my enlisted goals I terminated my enlistment and re-enlisted in the ROTC.
I secured my degree and a commission through in 1974 and enjoyed a long career as an officer.
Having lived the life of an enlisted man and NCO I acquired the knowledge of what that life was like. (One will never fully appreciate it without living it) That experience allowed me to temper my command practices and most importantly, my decision making in terms of always considering how that policy or decision will affect the individual soldier. It served me well and I've always considered the time spent as a premium asset when my performance was measured against my contemporary's.
I wish you the best in your career choice and would be interested in knowing what you finally decide.

Go to college. Major in a CAT 4 language. Try going all source first then try to go HUMINT Officer if you feel college is for you.