4 countries in 10 days - are you kidding?

I second the previous advice. Pick 1 country. You will be travelling to much and at the end you will loathe spending your time moving from one place/country to another.

If you have never been to Asia before I normally recommend Thailand. It is easy to be tourist, everything/most thing works, cheap and you really can't go wrong with 3-4 days in BKK and the rest at either Chiang Mai or Phuket - the latter if you prefer to relax at the pool/beach after sightseing in BKK. December is high season though so hotels rates in Phuket will be quite high (by Asian standards).

However, in December it is likely that Thailand is still mourning the death of their beloved King and it may also affect tourists, in particular if you want to go out at night, drinking etc.

Spending 10 days in Indonesia could be an alternative. Fly into Jakarta and travel eastbound in Java ending up in Bali or by returning to Jakarta. A classic Indonesia/Java trip with many interesting/cultural places to visit on the way - it can be done in 10 days.

As a first time visitor to Asia I would not travel to Burma - it will be very different what you are used to and only for the more seasoned travellers to Asia.