I have not sold anything on eBay for a long time and this is what came up "We've missed you. Start selling again on eBay to see your seller standards dashboard. Start selling Learn the selling basics" Does this mean I have to open a new account?

I have not sold anything on eBay for a long time and this is what came up "We've missed you. Start selling again on eBay to see your seller standards dashboard. Start selling Learn the selling basics" Does this mean I have to open a new account?

This is fine, it just means you need to list and sell something to get the seller account active again (or for the first time). Perfectly normal for ebay and you should not open a new account.