The scoring is spelled out at:http://www.warcraftpets.com/help/#petscore
Comparing you to Wyrda at 52 shows that while you both have 601 Unique pets all level 25 Wyrda has 3 more rare's and 1 more level 25 pet which matches up exactly with the 4 more points they have than you.
Some quick checking on the collections bears out those statistics. Wyrda doesn't have the three alliance side pets for the Argent Squire and the guild herald and page. Wryda also has all 4 RAF pets while you seem to be missing the two pigs?
They seemed to have leveled the RAF pets but don't seem to have leveled the Dread Hatchling or treasure Gobblin but they don't show a level at all so might have been manually added. If they actually have both those pets and have leveled them they could get 2 more points by updating their profile and would have 3 more rares and 3 more level 25 pets than you.
You should be able to spot these types of differences easily using the compare feature to just show the "Only if in One Collection". That's what I did and compared you both to my collection.