That bag is very nice indeed! Well done!
I don't sew...I guess I just made my compliment worthless...:p hihi...Anyways, I had home-ec in 7th grade, learned the basics of a sewing machine, know a few seamstress, hem my own pants whenever I'm not too lazy, so I do know a few things about sewing. Yes, you'd need a different needle for thicker fabric. And in some cases, you may even need to change the presser foot. However, in this case, that wasn't necessary.