Knee walking

Hi, I used to do TKD but just started Aikido and really enjoy it. Out of learning the basic moves rolling is ok (I dont mean Im good at it, its just I am getting better) but knee walking is really hard and painful for me. I have really long legs (why I used to do TKD) and currently have a bit of an ingrown big toe nail that really hurts when I knee walk, both of which make it difficult.
Am I weighted wrong, should I be more toe heavy or knee heavy? I know knee walking is important in Aikido so I want to get it right. Any advice welcome. Thanks.
An Aikido rookie.