Hi, nonumithu02;
My best advise is that you go for your DDS here in America. I have been working as a DA for 4 years, because I was geting ready to apply to Universities in US. You don't need any extra studies to work as a DA in US, unless you want to become RDA. You could alo pass the National Hygiene Boards, and work as a Dental Hygienist.
In my point of view, if you are a Dentist you have to go for your dental degree. It's quite stressful, and you need to study a lot, but once you made it to the Dental School, you are almost there. If you don't even try, you might feel frustrated one day, when is too late.
Of course that this is a personal decision, but beleive me, is not pleasant to work as a DA for ever. You always want to be on the other side of the chair, doing what you know. Besides the money is not good at all. You can do it temporarily, until you get to School, wich would be great for your resumee. But if you believe in yourself and think you can do it, go for your degree.
1- Take NBDE part 1. Better chances if you score above 90.
2- take Toefl
3- You can either go for NBDE 2 or star applying to schools here. Depending on wich school you intend to attend.
4- Get all the paperwork ready fr schools applications, specially letters of recommendations. Do this WITH TIME.
5- Once you are called for interviews, start practicing for the admission practical test. You might want to consider Duggan's course in Newport Beach, CA. It will cost you $2800 plus all the supplies, but I think is worth it.
6- Go to Interviews, prepare as well as you can.
7- Start praying 🙂
I hope this helps. Good luck to you in whatever you decide to do.