Congratulations on your college acceptance!
I'll echo RJM, college baseball is like a second job. Second to college academics. Hopefully, you'll really like your jobs.
My sons have played D1 and D3 baseball. Schedule wise, the most substantive difference between the two is the number of Spring games and the impacts (travel, missed classes, etc.) that occur. Fall (while technically a shorter practice schedule at D3 than D1...in reality, not so much) and Winter are pretty similar. And they are a grind.
Your first job is as a student. College can be harder for many people than high school. The safety net of home is gone. You're on your own to make the grades, identify the resources to help you do so, etc.
How about eating and sleeping right? No Mommy or Daddy to make sure that happens. What about drugs and alcohol?? You'll be making those decisions.
Baseball includes conditioning, weight training, practices, scrimmages, games, etc., and then throwing, fielding, and batting on your own. My youngest has early morning lifts (5:30am or so) required 3x per week. Conditioning in the afternoons is also 3x per week. That was through finals. Prior to that, the team was weight training (3x), conditioning (3x), and practicing (4x per week, mostly scrimmages, and those were 4+ hour days of that). Do you really love baseball? This isn't high school. When are you doing your school work? Heck, when are you sleeping??
In season at D3 there will be ~40 games. Presuming you make the roster coming out of Fall (oh yeah, tryouts!), do you make the travel roster?? If you do, you'll miss some classes. Hope you see your professors because they tend to be unforgiving.
Do you even play??? On a roster of 35 guys (though D3 can have many, many more) roughly about 20 will get meaningful playing time. Some guys will get zero innings, zero at bats, zero anything. Do you still love it?
You might play a lot and then get injured. It was really hard for my youngest to type papers wearing a sling on his arm last Spring. That was after walking around campus on crutches for a few weeks in a boot.
For my sons, they love it some of the time. Many times it's a slog. At 5:30am lifting is a slog. At 4:00pm in 20 degree weather running sprints is a slog. But they love their teammates and the camaraderie of the experience. They really love baseball. And they've learned some great skills like time management, healthy eating and sleeping, teamwork, etc.
Good luck! College sports can be an incredibly rewarding experience. And it's very, very hard.