What Causes Irregular Periods?

Hi I am 32 yrs. old and I have never had a pelvic exam, I guess it is because I am nervous about anyone looking in that area. I have never been sexually active and I have been having irregular periods for a long time. Should I make an appt. to see someone to discuss this issue? My last cycle was jan. 17th 2011 and I just recently started another cycle on may 2nd.