when i first started binding quilts it seemed to take a long time- i would work on it for an hour or so- then put it aside for awhile- a few years later- i have certainly sped up! now i can do the hand part on a queen size quilt in about 3-4 hours
used to take days!
practice not only makes perfect- it also increases your speed
don't worry about how long it (should take) it SHOULD TAKE AS LONG AS IT TAKES!
everyone is different with different skills- and work at different speeds