need some kitten advice...please

My cat Lily had kittens three weeks ago. They are doing great and are happy and healthy.She moved them under the bed the same day she had them,and they have been there ever since(this is in an upstairs bedroom,where it is quieter),I left her to it, as I have 4 children ,and I was concious of the kittens and Lily needing peace and quiet,and not disturbing,although I did check the kittens frequently.
However,now they are 3 weeks old I want to start litter training them and socialising them.
Every time I go near them,Lily is right there within a second,she is never aggressive with me,but has to see what I am doing.
Should I move them downstairs? I feel like they need to get used to household noises etc and be handled to make them socialble and I need to litter train them,but am worried about Lilys reaction.
Could it be too soon to do this?
Just really need some advice,as this is her first{and last} litter.
Many thanks

Mom cat can help with the litter training. I don't think I would move them in case mom gets mad she will put them back or somewhere else...

I would just put a small litter pan in with them and let the kids go up for a short visit every so often as long as mom doesn't seem upset by this. If you move them and she isn't happy she will just move them again so won't do you much good. GL with this! if you put the literbox in there though mom can help show them how to use it and if when you are in there you notice that they are looking like they have to go then you can put them in. Also let mom see what you are doing when you are visiting and watch her for signs of not liking it. if she is ok with it then continue on and make sure to give her some lovings too.

3 weeks is a bit young for litter training, but you can put a small one in if you want. Usually they don't start using it until eating solids at 4-5 weeks.
I agree with momof3 I wouldn't move them if she is happy where they are. You should handle them while visiting momma so they get used to it.

Yeah, it's early yet. They won't start really taking an interest in litter training until next week, maybe not even until week 5 or 6. The best thing you can do next week, would be just to move momma's litter pan (should be shallow so babies can get into it; please use non-clumping litter as babies like to "taste test") close to her, so that she can model the behavior to her little ones. If this happens, they do tend to pick it up on their own. Be patient! These things can take time!

They say Kittens should be with mom for 10 - 12 weeks so I figure you have a few weeks left to go then worry