Bilinguality is not a marker for a language capability. By taking up too much at once, you might mess up your chances for success but you also might be that person that actually can do it. No one but yourself can figure that
Im trilingual with basic capabilities in 3 more languages.
In high school i was already bilingual, and was taking 4 more languages. I failed two of them, and attained only basic understanding of 1. So i achieved fluency in one.
In uni, i was taking also languages. I failed one of them (it was one of the failed ones in high school... effing French!) and got basic understanding of the other 2.
Possible explanation? I dont have the talent for languages, it is an extremely hard work for me, that in my case demands total immersion, not classes.
My brother on the other hand has this unique talent, of being able to pick up new languages, including regional slang and dialects, on the fly.