Hi Mary:
God does not hold us to the impossible, nor does he ask us to do something which is imprudent.
In your best judgment, with the desire to go to Mass if you physically could do so without endangering yourself or others (and yes, getting stuck on a hill, maybe having to walk and make yourself at risk for injury, or having to have other people risk THEMSELVES to help YOU, is endangering), if you made a prudent judgment that the risks to yourself and others were too great, then you certainly did not mean to sin, if sin indeed there was. I know that in my northern diocese, the bishop himself has reminded us that if there are severe weather conditions or if one is contagiously ill, one should NOT attempt to go to Mass. You can always check out what YOUR diocese says, too.
But when you go to confession before next week’s Mass, if you have any worries, tell the priest. He can reassure you; if either of you have any doubt of the situation, he can also absolve you if sin was involved. It’s a win-win situation.