Congratulations to your husband for being accepted into Medical School. It is a HUGE accomplishment.
My husband is entering his 4th year of medical school this summer. It is his 2nd career and he is in his mid30s. Our kids are 1 and 4.
Because my husband is nontraditional most of his classmates are in their early 20s and don't have kids or even spouses so that cannot relate to what life is like being in med school with a family. It has made it hard for me to make any connections within his school. This is frustrating as I it would be nice to commiserate with someone who understands what I am going through. Hopefully your husband's school is bigger and you meet other spouses that are similar.
Though the schedule in Med School isn't too demanding in the beginning, what is demanding is the amount of studying they need to do, especially if they want to honor their exams. My advice to you is get used to spending a lot of time alone just you and your child. Be ready to do most of the childcare, cooking and cleaning alone. I think if you can have low expectations for the amount of time he can give you and your child then you won't have resentment towards him later. I hope I don't sound like a downer my husband is a great father and husband he just cannot devote as much time to us as a "normal" father/husband could. I think if my expectations were lower our adjustment to the med school life could have been smoother. Since my husband's school didn't have a spouse group I found Mom's groups on meetup and keep my boys and I really busy with playdates and other activities.
My husband has a classmate that is married with a new baby. He is barely passing his exams and won't get into a good residency because he doesn't study enough to get the scores he needs to be successful. My husband, on the other hand, studies a lot and is top of his class. Though he is gone a lot I'm so proud of him and I'm glad our children will see what determination, hardwork and perseverance look like :)
Blessings on this new journey in your lives. Find outlets right away and it will make the transition easier.