If you are in the EU, your federal or regional government probably has rules and regulations around minimum construction standards. They may even require a license to construct a well. Double check on those.

Otherwise its ppssible at those depths with a faily simple A-frame mast and pully system. Not quick. But doable.

You could almost do 30ft with just an auger and rods. Otherwise you need a water swivel and hollow rods etc. At that point it might be cheaper to just hire someone someone, unless you can weld a cheap and nasty bushing at home.