If AB offered this connection and you have both flights on one ticket, you should be ok.
Not only that TXL is a small airport, but if you have booked it as offered by AB on one ticket they should know you are coming and make arrangements for your individual transit, should time make this necessary.
They are really trying hard to offer a good service for international transot customers at this makeshift airport, but certainly everywhere things can go wrong. So if you have some status membership with Oneworld or Etihad, state it. If you check baggage through (which might even help to make certain they become aware you will transfer), make certain they put a big "transit" or "short transit" badge on it and if possible also a "priority" badge. TXL is quite good at tight baggage transfers, but put all necessities in your handluggage!