So Confused... Low GPA College transfer but still want to get in university

After the 3rd semester I got 2.73 GPA… Hope I can get 3.7 on 4th semester
but i think it is useless because College transfer to university min GPA only calculate the 1,2,3 semester grade.
Took Cal I (C-) and Chem I (B-) and I really want to get in engineering majors.
But now I just want to get in a good university.
First choice is Ohio State University.
Do i still have the chance to get in?

Not really, especially not for engineering; Ohio state wants a 3.0 from transfers.
You should plan to spend one more year at your community college and take more pre-requisites, or attend a branch campus then change campuses.
For instance, are you saying you’re in Calc2 right now, as a sophomore? If so, how well are you doing? Realize that to be competitive for engineering, you’d need one extra year of math, one exta semester of chemistry, and of course the usual physics I&II, English I&II, etc.
What do you plan to do to get a 3.7 average this semester?
Your current GPA qualifies you for an Ohio state branch campus though - and once you’ve completed pre-requisites and brought your grades up, you can change campuses to go to Ohio State’s main campus.

Your Calc 1 grade doesn’t gibe well with the engineering major. You need to be much better in math.

I am 2nd year(sophomore) in CC. I am taking Chem II, Phy I and Cal II right now. I took English I & II already. Is it easy to change to main campus from branch campus? And can I change the major after I change to main campus?

Yes, it’s pretty much automatic to “switch” if you have the grades (you don’t have to apply, you just move on up).
Some have housing.
https://housing.osu.edu/living-on-campus/regional-campuses/
OSU Mansfield is the easiest one to get into, they’re building residence halls to attract more students, but check that they offer the classes you want (Physics II, Calc 3 or equivalent, etc.)
http://mansfield.osu.edu/
OSU Marion has no on-campus housing but offers privately-owned student apartments. It’s a bit harder to get into but it’s not onerous. It can be a nice step toward OSU Columbus.
http://osumarion.osu.edu/