Feeding a 5 month old bun

Hi guys! I just brought home a 5 month old netherland dwarf today. The lady at the petstore said alfalfa pellets and timothy hay was the way to go. Petstore employees don't always know for sure whats correct though so I want to check.
I also heard 7 months is when you switch from alfalfa pellets to timothy pellets. Is that correct? Thanks!

You could switch him to timothy pellets now if you wanted.
I generally say 6 months. But its not as big of a deal for those itty bitty dwarfs

Which pellets are you giving him? Give us the name and we can take a look at the composition and tell you if those pellets are OK - there are some terrible pellets on the market. You'll have to introduce vegetables too, but as you took in a petstore rabbit, it's very likely neither he nor his mother were fed correctly so you'll have to do it very carefully to avoid an upset stomach.
You can read this, it's a trustworthy website and it will give you a better idea of what's the ideal diet for your bunny :

http://rabbit.org/category/care/diet/

Alfalfa pellets to 6 months is fine, and then slowly transition to Timothy based pellets. It's your choice whether to introduce veggies to your rabbit's diet. It's neither correct or incorrect if you choose not to.

Hes been eating the Oxbow Young Rabbit pellets. They are the best I've found here in Canada. They made me buy a bag of it (store policy) even though I already had some at home. I will probably just feed him these for now and start transitioning him once the bag starts emptying. Im also going to give him some veges starting in a few days once hes more used to his new home.