Ok idk if to worry or be excited

So I had a doctors appointment today I see my doctor every week since they are checking my diet anyways I'm 32+3 and Doctor said I'm measuring 34 weeks my question is does this mean my baby can come before my 40 weeks and if so how many have had this happen that they measure ahead and baby arrives before due date or can I go on to my 40 weeks and end up measuring 42. Weeks by then ?