Hello! Welcome to paw talk
Yes lionhead usually stay pretty small. I believe the breed standard is between 3 and 4 lbs max. I have seen bigger ones though, around 5 or 6 lbs. My lionhead is an adult and 2.5 lbs, so he's just a tiny little guy. He kind of looks bigger though, because of all his hair.
Congrats on your new bunny!