User blog comment:FairyRaven/Fairy Tail Chapter 360:The White Inheritance, Review and Commentary/@comment-24066070-20131115194948/@comment-7418318-20131116084300

Yes she was a mage, kind of before she joined Fairy Tail, but she ran away from home and decided to become a mage only one year before she met Natsu.

Even if you count this time of dabbling in magic completely, that still leaves her with only a little under two years of experience at the current point of the story, while the other mages have been in Fairy Tail for at least as long as Happy is alive (six years), except Romeo, but he had seven years to overtake Lucy (in terms of time as a mage only) while she was frozen.