With your car being so new, you’ll suffer quite a big hit in terms of depreciation - always the heaviest in the first year, although if you managed to get a decent discount when you bought the car, that would lessen the depreciation impact of what you could get for your car if you do sell it.
Depending on your personal circumstances (whether you’d be carrying other passengers at the same time as your elderly mother) and the size of the wheelchair, you may find the
Cupra is plenty large enough. If it’s only you and your mother + wheelchair in the car, you can always put the back seats down if the wheelchair won’t fit in the boot space.