You don't need to be re-initiated into Kundalini meditation if you have been initiated.
Once initiated you have always been initiated.
You can raise the energy from mooladhara to agna at your will at any point of time.
It doesn't matter if there has been no practice even for a few years.
When you sit down and practice, you will feel the vibrations at agna.
Meditating everyday will help you increase your brain capacity and succeed in every dimension of your life.