how long would it take me to learn Arabic?

Depends on which Arabic. If it's colloquial, spoken, no harder than most languages, I guess. Could probably master basics within a few weeks if persistent and using good tools. If it's Modern Standard with grammar, probably a fair bit longer, depending on which languages you already know. Arabic works very differently from English, for example, but is close to Hebrew. If you want to learn the classical language, years, probably.