If it will make you feel better about your bow poundage, I shot thru a big eland bull with a 62# bow, in fact all 7 animals I shot I had a pass thru. It was my first hunt too. You will be just fine but if I were you I would have a fairly heavy arrow and a good performing broadhead.
Just got back a week and a half ago From my 5th african trip, my wife bowhunted also and took kudu, zebra, blue wildabeest and blesbok and shot completley through all with 50# and 480 grain arrows with magnus stinger 4blade heads. Make sure you shoot straight up the center of the leg, which seems foward on our game but if you study shot placement its killer!