Area of research for PhD????? To soon??

I went to see Prof RM on Monday 28/12/2009.. needed to have her signature for my annual performance report. I voiced out my intention to pursue PhD under her supervision... "Well, depends" she said smilingly. Then she asked me what I taught for KDC. I mentioned I taught ICT in BM focusing on PBL. Prof said PBL could be my angle of research for my further study.