Hi Arjun,
You have probably had this crush for your friend over a good chunk of your two year friendship with her.
Given that length of time investment that you have put into getting to know her, it would be worth it to go for her.
She may have a crush on some other guy but that doesn’t mean that she isn’t open to dating you. As long as she is single and available, she is fair game.
It is best to go for it now and find out for sure whether a romance can happen than to do nothing and ultimately live to regret it.