If your iPad is less than one year old, you should still have benefit of Apple’s limited one year warranty - which will cover faults or defects. If you opted to purchase Apple’s AppleCare+ extended warranty, you will have a full two-years coverage for repair of faults or accidental damage.
Either way, your iPad will not be usable with damaged or defective physical buttons - and must be repaired.
Whilst Accessibility features (such as assistive touch) can be used to augment the User Interface, these features cannot be used as a substitute for physical button sequences that must be used to trigger system recovery actions. Sooner or later, as now, you will encounter a situation from which you cannot recover.
Your best course of action is to visit the Genius Bar at your local Apple Store or Apple Authorised Service Provider (AASP) - where the technicians will be able to test and assess your iPad. Take along your proof of purchase - as this may be required to obtain warranty service:
Genius Bar Reservation and Apple Support Options - Apple