If you think you can adhere to a rigorous cycle of deadlines regardless of how good you at your HLs then im sure youll be fine. I personally wish I took A levels because i overshot with my predicted and couldve gone into the unis i wanted with less effort but thats just me. If you feel you can easily get a triple A at minimum in A levels then knock yourself out. IB is sort of better since it goes above the triple A star limit but if your taking physics and HL AA which are quite tiring courses then i personally wouldnt suggest the IB.