No. Asexuality is the absence of psychogenic sexual arousal. A mature person is a person who is able to interact with society as favorably as possible while maintaining his own individuality. They are not related to each other.
Harmony inside and outside, the ability to make decisions and be responsible for them - these are the signs of a mature personality. At the same time, sex life can be absolutely any. But if you have peace of mind, everything is as it should be.