I bet you did not need this forum, just your daughter's reaction to be glad you kept it all these years. Measure your success in the fun you have working on it, still lots of possiblities as noted above.
If the parts dealer is still around why not mail him a bunch of receipts from competitors when you get a little farther down the road, as a thank you for his encouragement when you were younger ? Too bad you let him color your thoughts for so long, but also shows how an ignorant comment can have impact. I might have felt the same getting feedback from an "expert" as a younger person but the older I get the more I reallize a lot of know-it-alls actually know very little.
