Can I give my guinea pigs mixed pellet food when I first get them?

When I get my 2 female guinea pigs in August, I don't just want to feed them pellets, but people are saying thats what you do when you first get piggies. I want to give them a variety of mixed pellets (dried fruits and veggies mixed in with the pellets) because it has a variety of foods for them, but I want to do whats best for them so please help me! (No trolling)