ADVICE NEEDED *NO HATE PLEASE*

So I met this REALLY amazing girl on the internet almost TWO YEARS ago. We really want to meet in real life, we video call, play xbox games with each other, on Facebook we act like we've known each in real life for years. We know so much about each and both of us have never lied. We're all about honesty, I'm 14 and when we met I was 12. I told her my age was 15 because I didn't think this friendship would last and I didn't know if she was actually "her". She now thinks I'm 17 ( she's 15 almost 16) and I want to tell her the truth about my age but I don't want her to hate me... She's such a loving girl and I want this friendship to last but she needs to know my real age... How do I tell her in the nicest way possible? Please ladies help! No hate, like I stated I didn't think this friendship would last and I didn't know if she was actually "her".