I bought 5 guppies in December, one died in May, June, one given away in June, and one died in October. I now have one left and he is getting on fine. Sure, he'd prefer some buddies but I don't want any more guppies.
You should be fine so long as you check your water frequently and don't put them with other tougher types of fish. I think it's just like when you get some fish for the first time and you haven't looked into proper care for them they may die, but the next time is more successful. Don't give up on them! You just need to look into them more and see how they need to be looked after more and what they like and don't like. They are very pretty fish, especially the neon ones :~)