When my wife started she started looking at 250s and such, because she was comfortable on them in the safety class. I didnt want to buy her one of those because she wouldnt be able to keep up well on rides/trips because some of those things dont top out high enough to travel on the interstate safely. Plus I figured she would 'outgrow' it very quickly. The blast would probably fall into this catagory.
We ended up get a lowered 883 used pretty cheap. The previous owner bought ALL the add ons. It had crash bars (very helpful), windsheild, saddle bags, etc. I did not have to buy all the accessories. She has dropped it a few times, broke a mirror, lever, blinker. All easy fixes and parts are readily available cheap (if you use OEM style stuff, not chrome).
Overall I would get a bike like a 883, buell 9, 600 metric. Something like that should be managable enough to learn, cheap/easy enough to fix (except maybe the buell) and she wont out grown it in 4 months.
Just my thoughts.