Should we wait to sign up for an ad program?

We've been running a passion project, travel blog (hosted on Square Space) since 2018 and are finally enjoying a substantial increase in traffic.

Question is... should we wait to embed ads?

My partner heard that we should wait till our unique visitor count is at 50K+/month so we can start on MediaVine. We're averaging 10K+ unique visitors a month this year. Would prematurely signing up for a smaller ad program hurt our SEO?

Thanks in advance for your feedback and insight!