I met him on Facebook and now going out with him, and I told him I was 16 when I'm 15 and he's 18 what shell I do??

Only one year and I think it is nothing, maybe he is forgot.

Okeey thanks, because he told his mum and dad I was 16 so don't no what I should do?

Depending on where you live, 15 is not the age of consent. You need permission from your parents to date him and if there is anything sexual involved, he can be in deep trouble.
Tell him the truth. Starting a relationship with a lie never turns out well anyway.

Only one year and i think it is nothing, maybe he is forgot.

One year is more than nothing if she is not of age.

But I think 15 and 16 are no different.

At 15 she may not be of legal age. That makes a big if he is 18

But she only said she is lied of his age.

Reread it. She lied about her age. She said she was 16, she is 15. He is 18

But i think 15 and 16 are no different.

Simple fact... it doesn't matter what you think, it matters what the law thinks. As Homegirl said, it could be illegal based on where they live... even if YOU think it's OK.

It means in many places he things you are old enough for sex, so if you have it, and he does not know you are 15, he can go to jail and it is not his fault.

Next what happens if you are together and he sends you a happy 17 things to you home,

He will find out if your stay together, so you break up with him or tell him the truth.

Ok, it is a little serious, but you should face it.

Tell the truth maybe he'll understand besides your not far off from 16 just don't let anything sexual happen .

Thanks x