Yep, that's totally normal! We have a 3 1/2 year old male that basically just lays in his plants all day. He'll do one or two laps around the tank to patrol his terriory, and then chill the rest of the day =)
My Current bettas:
Sullivan- Orange rose tail halfmoon male
Daisy- Mustard Gas (black and yellow) veil tail female
Milton- Teal butterfly halfmoon male (mom's betta)
DFTBA to nerdfighters working to decrease world suck!