What girl advise should i give my 13 year old son?

I work at my sons school as sub. He's short not very popular but always got a valentine or two every year.Hes been constantly laughed at for his height.He never had a real girlfriend.Although i think he looks great with his waves.I should stop baling about him.Anyway theirs a girl he said he likes and she was his last valentine but no more they didnt do any valentine things.He want to make things go farther than a friendship but doesnt know if she likes him seeing as the've been close friend for 2 years.Please i want my son to look to me for advise.