Thank you for all your suggestions . . . forgive my ignorance, but what is "rim tape"? The mechanic made no mention of that to me. I'm fortunate, as I do have a great relationship with the mechanic as well as the "bike guru" of the shop - he's been great with me and he did show me how to change the tube - he had done a demonstration when I first purchased the bike, but I was more interested in getting my baby out onto the road than following his instructions - I was just in another zone!! When I took the bike in for the first flat, he did show me again how to change the tube and I did a little demo for him just to make sure I was on the same page. Then I took it back again (after 2nd flat) because I just thought it was strange that it occurred again, and so soon. Today's tube, I changed, and each time, the wear has been near the stem. As suggested, I think I'm going to purchase a different brand tube and see how I do with that (if this one goes). In the meantime, I'm just a little freaked about riding and constantly looking between my legs to see if my tire is alive, and, every little bump I hit, I'm wondering if it's the tube or the road. Perhaps because I do all my riding alone, I'm just apprehensive about riding now.

Again, thank you for your responses - so truly appreciated.

Kathryn