Hello again Dek @Sharma,
There is no age limit for most of the Ausbildungs (vocational training) but there are requirements for them, depending which Ausbildung it is.
For example, for most of the ausbildungs you need to have B1 or B2 German certificate, or you need to have school ceritificate for some of the Ausbildungs. Especially if they have something to do with reading, writing and calculations.
Finding a vocational training is like finding a job. You should apply for them and it always help if you do an internship in that field before.
I hope I could help you. Once again, if you have more questions you can contact us directly.
Telefon + 49 (0)30 68 05 43 77