This does not seem to be possible, without contacting Shopify support
Check General settings https://<yourstorename>.myshopify.com/admin/settings/general
This is the currency your products are sold in. After your first sale, currency is locked in and can’t be changed.
But it also says this
You’ve made your first sale, so you need to contact support if you want to change your currency.
So it seems to be possible