I have an e-commerce website built with magento.
i working on a new theme, and it is faster and more optimised then the old theme.
My question is would theme changing effect my ranking ?!
In short: changing your theme very well might affect your rankings.
This might be caused by (a combination of) the aspects below:
imgare placed in the source code.
Make sure you monitor any changes to your website before and after you're starting to use the new theme to make sure any issues to your website can be fixed afterwards.