Unless you’re using kviek, the yeast will be fine. It’ll be slow but fine. If you’re worried, test your gravity at your normal ferment period (I usually do 2 weeks) and then give it an extra week and test again. If it hasn’t moved, you’re done fermenting. Heck, you could leave it a month longer and still be ok. There are always tales of “I left this in the back of my closet for a year, is it OK?” and it turns out fine.