Nuk pacifier ages??

Can I give my 11 week old a 6 - 18 month pacifier? I see that the ones for older babies are bigger, but is it bad to give it to him before that age? I had to throw out his 0-6 month pacifier today because I noticed it was pretty gross. Should I give him the big binky or go get some more smaller ones? Here's a picture to compare the sizes: