I have completed AME training. i really wanted to design aircraft .?

i always dreamt of designing aircraft.. but i din know any thing about this field.so i landed in maintenance Engineering. it was not real eng but some kind of diploma.i have applied for AeSI and give 2 papers in this JUNE session.Is it really good,doing that (AeSI) in full time from any coaching centre? can i do some CAD courses meanwhile... i am really confused what to do !!! help me ....