How could i find out if i have Norman ancestry?

The way to find out is to start your research into your tree, start with yourself and work backwards, ask to see your parents marriage certificate and divorce papers, these will give you lots of information...and you mother will have them so you don't even have to go and research this...if she can't find them get the dates, place etc and look at the records for that area........your own birth certificate will give both your parents details, name, place of birth, occupation etc