I started my baby at 14 months and she still cries at drop off after two months! It’s hard at first but you get used to letting go. They get to learn and play and seeing pics of them having fun makes you feel better :)
Sounds like you're doing it for the right reasons! Our first took about 2 months to get comfortable at his daycare part time. The school seemed to be helpful with the transition and using a comfort object. His class was small too so he had a little bit more attention.
Understand that it will take time for him to adjust to a new setting. And talk with the daycare to let them know that this is his first time