Hi Maura, Welcome to WikiTree.
You will likely run in to common ancestors as you add more of the ancestors.
One day you will start to add old Great Aunt Maude and find that she is already here. When you say "Yes, thatʻs my Maude", WikiTree will connect her to your tree and like magic all of her ancestors will be connected also.
Come back to G2G with questions anytime. There is always someone here to help.