becoming sexually active can change your cycle to begin with
I agree with Clysta, its very unlikely you were pregnant (but not impossible).
I would suggest that you take a home pregnancy test at least 2 weeks after this happened for confirmation.
If there was no ejaculation or penetration, pregnancy chances would be next to none. You need sperm inside the vagina (or close to it) for pregnancy to even occur. Otherwise there would be nothing there to fertilize an egg. You can take a pregnancy test with first morning urine if it makes you more comfortable. Keep in mind though that stress and sometimes starting sexual activities can cause a period to become late and delayed.