Loading time of the pages should be between 2-10 seconds, of course, lower means better. There are some web sites / tools which can help you in calculating the loading time of your web page, try these:
PingDom [MOST accurate]
Net Mechanic [No need to enter your email id]
Although they are self-explanatory, AND you must try out each of them, but if you want to have an absolute quick look, then the last option is enough (RobertJsteiner).
And if you want to see in detail and optimize the content of your web page, then see the results from Link vendor and Net mechanic carefully.
Loading Time Optimization
And of course images can also be very heavy too, so try to change most of the images to .jpg or .gif before uploading and it is much BETTER to re-size the images first and upload, than to decrease the width of the picture through HTML codes [You can use this tool to convert the images].
In blogger, you have the option to change the number of posts to be displayed in the main page, so try to keep them in 5-8 range.
And of course, you MUST show expandable posts with a “Read More” link, instead of showing complete posts in the Home page (so by this method, you may show more than 8 posts too)
Even after trying all these tricks, if your blog still takes a lot of time to load, then you should change the template and see the difference (do not forget to take a back up of your present template and widgets before doing this)