Could I be farther along?

Im pregnant and dont know when my last period was so the place i went to guessed my due date until i see my doctor and get an actual dating scan which im going on the 24th of this month. But they told me last week i was 8.5 weeks but i think i could be farther along then that because i swear i can feel some movement in my belly... this will be my second child but ive had 4 pregnancy all together. I was pregnant in december but then started to bleed so i thought i had a miscarriage..but i didnt go to the doctor to confirm because i was bleeding and thought for sure i miscarried. is it possible that i really didnt miscarry and i could be farther along.. I thought i had my period in dec and jan-febish but im not sure... is it possible i could get my period the first few months and actually be farther along then i think?