We took our son to a Spring Training game and he was about that age. We had lawn tickets though which worked out super nice bc we were able to bring our stroller and diaper bag with everything we needed. We brought the headphones but it was not needed bc it was not loud on the lawn. Our son took a nap, ate, and seemed to really enjoy watching people.
I think he will be fine
Have not been through baseball game with a baby, but I can say for other noisy events that some noise canceling baby headphones on Amazon were a great purchase