W..
Your cycle is not regular if it varies by that much.
You can almost set a watch by my period. I have a 2 day variance - sometimes I get my period 27 days after the 1st day of my last period and sometimes it's as late as when I get up on the 29th day. But I could look at a calendar and tell you in 3 months about when I will have my period. I can also tell you about how many tampons I will use during my period because it always lasts 6-7 days. Sometimes the last 2 days drag out with some spotting but that's as much as it varies.... I would call that a regular menstrual cycle.
An irregular cycle isn't necessarily bad and it usually doesn't indicate anything is wrong, per say. However.... since it's on the questionnaire I would write down everything that you can remember about your period - even in the last 3 or 4 months. She will get a picture of your cycle.
Good Lcuk