If you known her for a short amount of time it's not love. Or highly not. More like infatuation. Not a good idea to think about telling her.
But if you known her for a long amount of time, why not tell her? I suggest you just relax, don't worry too much, otherwise it will prevent you from what you want to do. Near the end of your conversation, she could say she's gotta go but you say, "I love you." Leave it from there... Next time you speak she may bring it up, it's either negative or positive. If it's negative just laugh about it (express it) and say, "I mean friends." Positive then tell her how you feel.