Golden rule for beginners, never be tempted to do something quickly with Google. The issue is that there are a lot of policies and you as a merchant need to read and understand the rules. Failing this may have seriouce consequences. For example if you are drop shipping, then you will get a life time ban. Or if you sell medical related products, not removing statements and claims. There are a lot of other rules.
So if you go ahead and quickly set it all up without understanding the regulation nor setting up the feed correctly will create bigger problems then if you would prepare first.
The Shopify API is a great tool, if your data is already cleaned up and does not violate any Google policies. However if you need to clean up the data feed consider my application, which allows you to setup import rules and also manual edit every single attribute.
If you have questions, let me know.
You can use this app https://apps.shopify.com/google-shopping-feed
This apps will help you upload the product within few min but there is small monthly fees are there which is about $4.99 & You can use it for up to 500 products but if you would like to go above the 500 Products then you can change the Apps pricing plan as well