Your time for starting a Charter challenge is not always unlimited. It depends upon the type of remedy you are seeking.
Striking Down an Unconstitutional Law
If you are seeking to have an unconstitutional law struck down, there is no limitation period. You can bring the action so long as the law is in force.
Personal Remedies
If you are seeking a personal remedy (for example: if you’d like to receive money as compensation for a breach of your Charter rights) then normal provincial limitation periods apply.
In Alberta, time limitations for civil actions are governed by the Limitations Act, RSA 2000 c L-12.
The general rules are set out at s. 3, which sets a two-year limitation period for civil actions. This clock starts ticking from the date you knew, or ought to have known, that: (1) an injury occurred; (2) the injury was attributable to the defendant's conduct (i.e. a branch of government or government official); and (3) that the injury warranted bringing a proceeding. Aside from the general rule, there is a “drop-dead” date of 10 years after the claim arose.
Special rules apply in the case of minors or people under a disability. If you think these special rules apply to your situation, you should review the Limitations Act and speak with a lawyer (here).