First you have to understand lot of things in SEO.
PR is constantly updated and is not function of how well you have done your on page factors.
Toolbar PR which you see is of no value and may not be the actual representation of the actual PR. Yes it may be close the actual PR when Google updates it. Google also updates it every few months now.
If you page is only 3 months old it means you have hardly any links pointing to your page and so you do not have any PR.
I will suggest you read the SEO FAQ page at the top of SEO forum for better understanding of SEO and SEO related issues.