try to tell her that God is "super super super". He can do everything at the same time, similar to an Octopus. So, not only he cares others, but he also cares for her.
Most importantly, tell her that if she invites God to live in her heart, God will go into her heart right away. Since God is so "super super super", he lives in the hearts of those who invited him.
My daughter is now 4.5, she seems to understand when she was about 3.5...
Just keep telling her that God is just so extraordinary and He can do anything....