I started SEO 5 years ago. May be I should have done it earlier.
There are two ways in which you could learn SEO and make a living out of it:
1. Build a website / blog in WordPress, create a ton of content and optimize that content for search terms. This is a long drawn process as your domain (website) is very new and it might take some time for Google to rank your website.
2. Learn SEO by following experts and implement it for a business that already exists: You could reach out to your friend or anyone you know who owns a business and has a website. Once you get buy in from your friend / family member, you simply offer SEO help for free. While you are learning the ropes of SEO, you can put your knowledge to action. Some of the SEO Blogs that I follow: SEOByTheSea.com by Bill Slawsky, Moz.com (Rand Fishkin), NeilPatel.com, SearchEngineJournal.com and my recent favorite backlinko.com by Brian Dean.