I'd suggest taking the cap all the way off, and putting it back on again. Sometimes the cap doesn't thread in properly and it clicks like it is tight but it is not properly sealing the gas tank. That can cause the check engine light to come on. It will stay on for a while even with the cap on properly but eventually will shut off.
I understand your uncertainty about taking a trip, but I think you will be OK. If the check engine light is flashing, or if there is a problem with the way the car runs then I'd be more concerned. Keep an eye on your fluids and guages as you drive and hopefully the light will go off and all will be normal.
If you wish you can go to an auto parts store like Auto Zone and see if the cars computer has stored an error code and learn what it is.