Probably not. Rennet doesn’t go bad so much as it loses its ability to coagulate milk after about 1 year. You can still try it, but you will need to use more and be willing to possibly sacrifice your batch. It it’s been more than 1 year, you will want to get some fresh rennet.
An extract from the membranes of calves’ stomachs which contains rennin, an enzyme that aids in coagulating milk or separating curds from whey. Rennet-like enzymes, also used commercially, are produced by selected fungi and bacteria and are referred to as “coagulant” instead of rennet.