I don't believe there is an age limit for a student visa. You are never too old to learn. You just have to prove that the purpose of your trip is indeed to study.
That’s correct as getting a study permit is all about presenting a convincing case to immigration of the intent as opposed to how old someone is.
Granted age will be a consideration in assessing whether the intent is not just study long term but some other reason . Criteria are same for everybody, current qualifications, work experience, English language capability, ability to pay the fees/ living expense approx 25000 cdn per year and finally how attending a course in Canada helps when the applicant returns to their home country.