Battery Charge of a new Apple Watch

Hopefully it charges fine for you. You can check battery health from the watch directly, under Settings > Battery > Battery Health. My S6 which was purchased right away at launch time is still showing a max capacity of 99% today.

in general it comes charged a bit, i got mine charged, however if you face any fast draining battery, you should contact Spple Support or return the product to the nearest Apple Store.

I would think its quite possible, why not. The battery will eventually drain even if the watch is not being used.

Just curious but which series was it?

It's possible if been stored for a long time,although I have never heard of one with zero charge.

Which watch is it?.