I love a guy but i am 14 and he is 13 what should i do?

See love not always means sex. Love means to people happy with each other and can trust each other.And again you both are at a very raw age for all these things.So being in company with each other is not at all a problem whatever age you both are.
When you will be friends and if you like each other and decide or believe that you can stay in a relation with each other age again will not be a problem in future.May be at that stage it will not be even a question for you.
Medically also this little gap is age is not at all a problem anyway.
So,what I suggest for now is be friends . At least be with each other and wait for the coming times to decide .
And anyway for a girl hiding her age has never been a problem.Well after sometime when you people will be comfortable with each other you can discuss this with him and I guarantee you , no harm it will cause to your relation then.