Since Google has announced that next year they will switch to mobile indexing first, you should be busy preparing your site for this change. ‘Mobile indexing first’ means that Google will look at the mobile version of your site to decide how high you should rank. So if the desktop version of your site is set up brilliantly, but your mobile site isn’t responsive at all, you have a lot of work to do if you don’t want to suffer a rank drop over next year.
A great way to test if your site is at least mobile friendly is to use Google’s mobile-friendly test. This gives you an indication if Google thinks your site is fit for displaying on mobile devices. But don’t stop after checking this. The best advice I can give you is to visit your site on your mobile phone. Browse your own site for a while and try to click on every button, image and link to see what happens. Is everything working as expected? Can you actually purchase something on your site while using your mobile phone? Are all pages displayed correctly? You will see that most sites have some work to do this fall.