The expiry date shown in your online CIC account is the expiry date of your confirmation of permanent residency (COPR) document and not your PR status. You will need to land (activate your permanent resident status) before that expiry date. The COPR expiry date is usually tied to date when your medical report expire. Hence applicants will have different expiry dates as you both have noticed.
@ dvddecarvalho, your PR status will expire 5 years after your landing date. You can renew it then or apply for citizenship once you complete 3 out of 5 years as PR (Bill C-6 rule change as of June 19). As an immigration rule, you cannot do in Canada landing unless you make an appointment at a in Canada CIC office or flagpole at a USA/Canada land border to activate your PR. Why you ask? Because Immigration Officials have to confirm who you say you are in-person and not just issue you a paper to change your status permanently in Canada. That's why one of your COPR copies will come attached with one of your photo that you submitted for your PR card so that they can verify you in-person.
I hope this helps. Congrats to you both for making it this far. Cheers!!!