DAA and/or DAD

Greetings from the UK

My Sweetwoods Student Dulcimer has finally arrived and I can start to learn. So my beginner question is about tunings. 

Should I learn both DAA & DAD simultaneously. If not which should I start with?

I am inclined towards the DAA tuning because I like the "droney" sound of that tuning but I wonder whether DAD is more flexible in terms of playing with others and the various keys I am likely to encounter.

Your thoughts & wisdom will be appreciated.

Thank you

Eric