How hard is it to learn and how long does it take to learn three new languages?

[Apy]

I am a math major at my college right now and during the school year I spend almost all of my free time doing math homework. I have always wanted to another language but could not make up my mind as to which language I wanted to learn. My uncles’ girlfriend graduated last and majored in language. She is fluent in 5 different languages. I know this takes much time for most people, she was gifted and her parents started her off at a young age. This summer I am going back home as appose to the beach so I am not going to have anything entertaining to do. This seems like a perfect time to start learning a language, well more like two or three. I want to become fluent in Spanish, French, and maybe Arabic. So my questions are how long it will take me, realistically, to become trilingual in foreign languages. Also how hard is it for someone one to become fluent in multiple languages at my age, 19, and while going to school for a different major than language.