1. You may not have pinched the tube. If the tire's bead is not seated properly in the rim, it will eventually do what yours did.
2. When seating the tire near the valve, push the valve up into the tire and seat the bead, then pull down on the valve. Also, pinch the tire opposite the valve while you are doing this so it goes down into the depression in the middle of the rim and gives you as much slack as possible to seat the tire.
3. Sometimes you get a tire with a defective bead that just will not seat. Since your tire had already been used, I doubt this is your problem.
4. 700x32 tires tend to be thicker and stiffer than 23 or 25 tires, so may be more difficult to wrestle over the rim for the last few cm. Try to resist the temptation to use levers for this, as it is very easy to put a hole in the tube doing this.
5. Keep at it, and you will eventually get it. Perhaps the next time you have to go to the shop, you could ask them to let you do it and coach you, but pay the usual price (or ask a more experienced friend).

Good luck.