Sec. 475 Mark-to-Market Election Question and Tax Year It Is Effective?

For my seasoned daytraders or tax experts, I recently took up daytrading and I heard about the tax stuff and got a little scared. So my question is Sec. 475 Mark-to-market Election. In order to claim it for the 2021 Tax year, can I file the election when I file my taxes in 2022 for 2021? Or did I need to file the Election last year for this year?

 

I know, noob question, but a serious one. So please help, because my opinion is that it would not make sense to have to file an election for the current year in a previous year. Like literally until about a month and half ago, I had no idea I was going to take up daytrading. Decided to give it a go and I am up overall, but I traded some of the same stocks without waiting for the 30 day rules. So my issue is that even though I am up 7.6% overall, will the IRS be like "nah you are actually up 50% overall" and tax the hell out of me. Which at that point, I need to stop now and maybe get back to it next year.

 

So please help an aspiring daytrader, I am completely confused on this and it seems weird to make an election for the current tax year in a previous year's return.