That Mason Jar light looks like a good project to dip your toes into. You can always tinker and improve/modify, for example by adding the microcontroller into the mix. In the initial stages you can use jumper wires and breadboards which are great for learning. When you know you have it right, you can go for soldering the circuit. Trying to solder everything in the beginning can be a little frustrating if you want to change things and experiment. That’s not to say you can’t do it that way though. If you think you’ll have more fun learning to solder, then go for it.