Pyrrhus is generally correct. These rules can be found on the NCEES web site. However, not all states in the US, or Provinces in Canada are exactly alike in this regard, so check with your local licensing board to be certain.
To become a registered professional engineer, you need to document real in-the-field experience and only then will they allow you to sit for the Principles and Practices exam. Schooling helps, but it is not enough.
Like any certification I have earned (and I do hold a few), it is no guarantee of good judgement or subject matter knowledge. It is merely a certificate that places your name and your experience on a project. If anything goes wrong with the design, you (and perhaps your company) will be held legally liable.
The concept is very much like being the captain of a ship. No matter what goes wrong, the captain is responsible. Others may be liable, but ultimately, it is the captain's responsibility to keep everyone safe.
Spend some time reading about PE ethics (you'll need it for the exam anyway) and then ask yourself if you really want this. Sometimes, the answer may be no.