All my girls have been older, I've never had a puppy. I don't know what it's like to train a puppy.
Chelsea was 18mths, and I was her 4th (and forever) home, she took 5mins to look around the place the first day, hopped up on the couch, then to the back of the couch, laid down and looked at me, and she was home. I think she moved around due to a very high energy level - and to set herself up to meet me that day.
April was 15mths, and came from a breeder. She was too small to show, and too small for breeding, so she came as a companion. She took a Lot of convincing (around a month), but love won her over. She was a home girl who liked life on the quiet side.
Tilly is 4.5yrs, I've had her 2 months. She also came from a breeder. She's in between the other two, she started to come around to me right away, but with her being older, some things have been slower. She's very reactive to sound. She doesn't know some games, but play with her in a way she knows, and she's very playful. Trying to get her to play fetch has been interesting.
I've loved my girls being older, and truth be told, as soon as I heard that a breeder might have an older one to let out (Tilly), I jumped at the chance to meet her.
Good luck with your choice!