In Star Wars we see many Twi'leks, which all have lekku on their heads. The main Twi'leks we see are female, and one of the only male Twi'leks we see is Bib Fortuna. Bib Fortuna's lekku are very long; so long, that he has to roll it on his neck. The Female Twi'leks with lekku are all short, but all the female Twi'leks we see are relatively young, while Bib Fortuna is very old.
Does the length of your lekku grow as you get older?
Meet Numa.
In this picture she is 5 standard years old, living on Ryloth (22 BBY).
Here is a picture of the back of her head, with her full lekku showing:
About 19 years later, Numa is 24 standard years old and it looks like her lekku have grown, at least a little:
This answer applies to Togruta lekku, not Twi'lek lekku. The most obvious answer can be found in the canon animated series Star Wars: The Clone Wars. At the beginning, which takes place within the first year of the Clone War, Anakin Skywalker's Padawan, Ahsoka Tano, has relatively short lekku.
In the later seasons of the show, set during the Clone War's second year, she has longer lekku.
This should be a conclusive answer to the question of finding out if lekku grow with age.
Twi'lek lekku most likely grow proportionately to the Twi'lek. Bib Fortuna's lekku was very long most likely due to a not very good costume.
Lekku lengths vary. "Long or shapely lekku were considered great status symbols, and often went hand-in-hand with respect, influence, and wealth. A Twi'lek's brain-tails could be likened to phallic symbols, and for both sexes, larger lekku brought with them some indistinct positive connotations."
Lekku grow with age from a young age until adulthood in every lekku cousin species. They contain additional consciouses of the brain that all work together to do such things as solving crimes, and knowing what to do in a battle. The more lekku are had, and the longer, and thicker, the more superior the lekku person is over others in actual fact, such as being more intelligent. Just like Earth's fox youkai have different lower back tail counts to have different astrological meanings, the same is true of the headtail count, but the original home planet of the headtailed species group has at least fourteen Houses instead of Earth's twelve, so headtail count goes up to at least fourteen. All of the cousin species can intermix, like Kit Fisto and Aayla Secura.
I am a Nautolan.
