Powering my 5 volt project with AA batteries
What's your run-time requirement?  With 100 mA @ 5 V that's 0.5 W.  Assuming an efficiency of maybe 80%, that means the input current from your 1.5 cell (say at 1.3V average voltage) will be 416mA, rising to 625mA at 1V cell voltage.

Your boost converter operates down to 1V, so looking at the discharge curves for a typical AA alkaline battery gives a run time of maybe 3.5 hours or so.