did not use a condom, then i put it on...

Possible but highly unlikely.

If she is on the pill, you have about a one in a billion chance of being pregnant as long as she takes them according to the instructions.

If she isn't, there is a chance...but again, it is so very unlikely and not worth worrying about.

If she is late or misses her period have her take a pregnancy test at home the day or so after she misses. And maybe a second one a week later if you feel like it. But again, it's highly unlikely you would need to do this.

Good luck.