I started with tinkercad. There is nothing wrong with tinkercad. (Even if my mechanical engineer boyfriend snickered about it a bit.) It was a good introduction but it is super limiting, only able to use basic shapes and all. Now I use fusion 360, it was a bumpy start but I've got the hang of it and one of the most useful features is the fact that I can now make my cylinders tapered which means my buckets can stack inside each other, besides just being fancier. Now to add handles!