If you have never had your tires rotated, it is likely that the front and rear tires will have worn differently and you may need to replace one or the other sooner than the others. This isn't ideal as it is better to change all your tires at the same time. We would recommend taking your vehicle to your shop and asking a professional mechanic for their opinion on whether your tires are able to be rotated and the overall tread wear on all your tires.