There's a stickied thread about YouTube Red at the top of the forum - no need to create yet another one.
90% of YouTubers do NOT have to explicitly agree or it was already done in April - June 2015 and you've forgotten.
1) Click here
https://www.youtube.com/account_monetization
2) Click on the last line "Review your agreement with YouTube" - If there is a section 1.2 talking about revenue from subscriptions, then you're good to go.
