It seemed my was to big, but it was the one I took out of it. I did not use the sealant some people recommend. Are you pulling the seal over the rim with cord. I used cord and lots of rubber lube. Luckily I had a neighbor gal that weighed about 100 lbs that was able to push on the windshield while I pulled the cord. Watch this video.
https://youtu.be/TGimNuT6XyIi