Avg time on site: most people came to your website on average 7 seconds and then the close it back. That's why your bounce rate is also high..
Looking towards your stats, you have good visits, pageviews, 99% new visits but the average time on site and bounce rates are cause of concern, so work on your site layout, design or identify reasons why bounce rate is too high. Thanks!
I don't think you understand what that metric is measuring - it's how long people are spending on the page. As others have said, combined with your high bounce rate it implies that people just don't want to stay on your site. The speed of it's loading has nothing to do with it.