I had most of them as signed hardbacks, because Pratchett always went out on the road signing when a book came out. Handed the whole set over to a charity shop during a house move a few years ago. I have them all on Kindle if I ever want to dive back in.
It’s the beginning, so yes. But it’s also a bit rough and ready. Pratchett was still finding his feet. The first two books were more like straight-up parodies of high fantasy, and it was from book three onwards he started to really build his own world and use it to make points about ours.
So make your own call, I guess. I’d start there, but keep in mind that if it feels a bit silly and try-hard then things do (rapidly) improve with later books.