I need pierced ears help!!!!?

I had my ears pierced today. The shop used sterilized earrings and told me to leave them in for 3 weeks and clean them with alcohol nightly. However, my boyfriend gave me diamond studs set in white gold. The reason I pierced my ears was so that I would be able to wear these. Is it all right if I go ahead and soak them in alcohol and then change the ones I am wearing to these? Will it get infected or should I just listen to the 'shop' guy? How sterilized are the ones that they put into my ears, really? I sort of feel that it is just that he wanted to sell me the earrings and couldn't charge me $25 to just stab my ears. What do you think? Am I safe as long as I sterilize the new earrings?