I tried to test my website speed several times at pingdom, but i got Performance grade B alwasy, is there any problems with my website? is the website size problem? I installed many plugs on my wordpress.
If you use gtmetrix.com it will give you reasons for the slowness, and suggest things you can do to speed up your site, but if you have a lot of plugins you might also want to see if there are any you can live without.