It's better to confess your dishonesty than allow them find out the truth from another source.
Like this woman in this story here, the problem these people eventually encounter is how to confess later. The guilt nagging in their conscience never quite becomes silent. When you lie to someone about something as fundamental as your age, it has a way of affecting the relationship negatively. Lying generally has the ability to do this to any relationship.
So if you have lied to a guy or babe about your age because you thought it would increase your chances with them, one way to make things right is to come clean. Fess up about that lie now!
If you started off a relationship with a lie and your partner finds out, it could be the end of everything.
Only solution, however, is a sincere honest effort. If you tell him quickly, your lie is still more of a white lie – a silly and impulsive thing you did to get a date. If more time goes by and you don't say anything, you seem like a serious liar who is willing to manipulate someone to get what you want.
So the secret is to come clean as soon as possible. The longer you delay, the worse it gets.
That you come out clean does not mean they have to forgive you.
If your date chooses to leave, you do not have the right to be angry. After all, you lied. Whereas you may want a younger or older mate, that same person may not want such an age gap, or they may simply not like the fact that you lied. You can plead your case, but you also need to respect their decision and not take offense.
Results of that confession may vary. They could forgive and stay with you or they could end it. One unshakable advantage of coming out clean is that can make peace with yourself at least. And really not many things in this life beats a clear conscience.