for one.. you're stupid for making the mistake in the first place. at your age, i would have figured that you'd make better choices.
and if you are for real..this is what i suggest. i think that overall you SHOULD tell her the truth. being that you're 27.. you should already be man enough to man up to your problems. you already got your head stuck up so your ass.. so now what are you going to do about it? do the right thing..right?? exactly.
you shouldn't be afraid to lose her.. for more reasons than one.
1. first the obvious, the age difference.
2. you already messed up. i'm not sure what kinda 15 year old year old and a 27 year old could really have in common except for the fact that they both love to chat on the internet.
3. at 27, you're still peaking sexually, and you should be looking at women your age, not half your age.
i know that people will agree and disagree with me on this thread. however, you feel that you "need" her in your life, correct?? but have you actually took a step back and looked at things from her angle?? she trusts you and believes that you're 19 or whatever age you told her. being that it's easy that you already lied to her once, she will loose all her trust in you. it's a mistake that you have made, and you must be willing to pay the consiquences. think about it.