I think Antegy pretty much covered the bases with his/her post. I'd also like to add that I find baby burms calm down more quickly if they are handled for longer periods of time, instead of short amounts. It seems the longer they are out, the more time they have to get passed the initial freaking point and start to roam and be the curious little snakes they are. Sometimes, by doing only short amounts of time, the babies never make it out of their initial stage of being scared and are more apt to take longer bouts with being nippy.
Overall, I'm glad you're trying to handle this early. It's the best time. As stated above, I'd try working the snake up to at least 30 minutes out of the cage a day. The key is to find a length of time that allows that trusting bond to be built..without stressing the snake/you out too much. Good luck. Thanks for the post.
Sam