Period question?????

ok..my period fluctuates between 28 and 38 days..like one month it will be 28 days then the next 38 then the next 28 and so on like that..is this something for me to be concenrned about??? will u have problems conceiving?? my period used to be pretty normal every 28 days like clockwork but in the last year or so its been like this i am 20 year old healthy female..should i get tested for any disorders??