Assuming you have no luggage, and assuming the wheelchair folds up -- there should be no need to order an SUV (called Lyft XL). There should be room in the car's trunk for the folded wheelchair. However, that depends on the specific vehicle you get. If you get one of the really small vehicles, it could be a problem.
My suggestion is to call the driver immediately and explain the situation to them. If they can't/won't take the wheelchair, you just cancel without penalty.
One thing to be aware of: Your driver may not be willing or able to load and unload the wheelchair. Some drivers will insist on doing the loading/unloading to protect their cars from accidental damage. Other drivers will refuse to load/unload anything. It's up to the driver.