I recommend to check if you really need a CDN (depending if your traffic is local or worldwide).
A lot of tools suggest a CDN and it seems like a quickfix, but it adds complexity and costs and most of the sites have local traffic, so it's not really helping (you just have some SEO / Pagespeed tools giving you a green checkmark saying "great you use a CDN, but actually your site is not faster for your local users).