M.K.
Speaking as a mom of adult children; I encourage you to talk with your mom about your feelings and the difficulties in it. Of course, you have the option of meeting with your family for Thanksgiving on an every other year basis, or of inviting them up when you are hosting. An hour to drive is really not that long, even with three kids.
With my own adult children, I have had to learn "flexibility" with having two living out of state. Last year, between Thanksgiving and Christmas we were not even all together at the same time. That was very hard for me, a person who has worked hard to build traditions that we have enjoyed all these years. I have learned that a "holiday" does not have to happen on the exact day...last year we had "Thanksmas" with Thanksgiving on Thursday and Christmas the following Saturday because my daughter and family were only in town for Thanksgiving weekend and would not be back for Christmas...it worked. The hardest part was not also having my son in town, who could not be here for Thanksgiving but was here for Christmas.
We have had Easter celebrations the week before Easter and Thanksgiving the week before or after Thanksgiving.
The day/date doesn't much matter; celebrating as a family does. Even though you have your own new little family, you may not realize that your moms love flows as deep toward you now as yours does toward your one year old!!! A moms love doesn't change because her child becomes an adult.
I encourage you to have a conversation listening with your heart. Good luck.