@Dhananjay ,
Whoa, cowboy, back off from the love talk.
You are attracted to this woman. You perhaps have a crush on her. But
love is a different story. God, I really wish people would stop misusing that word.
By the way, when it comes to most people, if you suddenly blurt out that you love them, it rarely goes well. Life's not like the movies.
How about instead just asking this woman out? In the context of
liking her. You
like her. And that's terrific. Maybe she likes you back. Maybe she only likes you as a friend. You will never know unless you ask, but if you start up immediately with love talk you are going to scare most people away.
Will it affect your 13-year friendship? I guarantee it. Either way, the friendship will be affected. Decide what you want to do, but trying to take it to the next level will change things permanently. Whether that's to good or ill cannot be determined from my chair.