WWW,
soloing a student is the scariest thing CFIs do. you can only do your best. Once, a good academic student with hard won flying skills failed the PPL ride due to stalls. A few hoursextra training and he passed the next week. I moved the next month and he crashed into a graveyard tryng to turn around and return to the runway after an engine failure. It seems he ws checking out in a Bellanca Super Viking (from a C152), had a CFI on board when he went in. I still wonder if I could have done anything better in my training and it was 20 years ago. Both died. On the upside, many student tell me that on every final approach they make, they hear my voice saying, "if the airspeed is right everything will work out fine." I promise you'll have way more good feelings about your decisions than negative ones.