According to the document, we know:
Restaking Points: A measure of your total EigenLayer restaking contribution. Based on amount of ETH staked over time, in units of ETH per second.
Points = ETH amount x Restaking time
For native restaking, I think the start time should be when the credentials are set to the EigenPod contract. But from the point I got, I found that the start time is the time my validator was active.
See this link:
https://preprod-goerli.eigenlayer.xyz/restaking/v1/pod/0x3Bda09943b6D0Eda1B4fdE3a7344897032b24061/summary
this link is the summary of the EigenPod contract 0x3Bda09943b6D0Eda1B4fdE3a7344897032b24061