Importing Wix data onto Klaviyo to integrate with Shopify

Hi guys, 

I currently have a Wix store with all of my customers on there, we do not currently use Klaviyo with Wix. 
We are switching over to Shopify and want to integrate our new Shopify store with Klaviyo. 
In order to get all of my Wix customer details onto Shopify and Klaviyo, I am wondering if there is a way to import Wix data onto my new Klaviyo account, that I can then integrate with Shopify, so that I have all of my Wix data on my new Shopify store with Klaviyo. 

I am unsure if the only solution to this would be to integrate with Wix first, and then switch over. If I were to integrate with Wix temporarily just to get the data, would this cause any issues?

Thanks