> When researching to confirm I thought APY was the percent of how much I would get as interest into my account.

Correct, if you are able to hold continuously for 365 or 366 days.

> But online says the APY is how much interest would be charged to me if I were to withdraw early.

Wrong.

> So say a 12m is offering 4.15% APY I thought that's the amount I'd get back so 100->104.15 end of month

$104.15 after the 365 days (1 year), yes.

> it being if I need to withdraw it'll be 100-> 95.85 I'd get back

No. Early withdrawal penalty varies from CD to CD. Read the terms for that specific CD. Sometimes it's 3-month interest, sometimes it's 6 months. You will also still keep the interest you earned so far. It's just that the penalty might be greater than the interest you earn.