Wood Mouse baby at 3 weeks old

Wood Mouse baby at 3 weeks old and it’s growing fast. It’s nearly twice it’s size when we found it and double the weight. Eyes are open, drinking and feeding itself and we are weaning it off milk. BUT it is still very cute. Next thing is to decide if it stands a decent chance of fending for itself and if it should be released. It has changed a lot from just a week ago when it was just on kitten formula milk.