The relevant provision for you is available here <
http://www.cic.gc.ca/english/resources/tools/perm/express/refuse.asp> and it states:
"An applicant may have a birthday after they receive an ITA but before they submit their e-APR. Their change in age may lower their CRS score below the lowest score in the round of invitations. It may also result in the applicant no longer meeting the minimum requirements of the FSWC and, consequently, no longer meeting the MEC, resulting in a refusal based on section A11.2.
When a change in age results in the candidate no longer meeting the MEC or having their recalculated CRS points score fall below the lowest points score in that round of invitations, officers should consider applying the public policy to exempt applicants for permanent residence from certain age-based requirements between invitation to apply and application, based on section A25.2. This consideration can result in an exemption from the refusal of an application under section A11.2.
This public policy also grants an exemption to applicants who may be refused for failing to meet FSWC program requirements when their birthday occurs between the ITA and e-APR."
The above coves the situation when the birthday falls after ITA and before the e-APR is submitted. But if your in the pool and the main applicant has a birthday, the applicant's score will go down based on the age.
Now I cannot predict if the score will drop below 470, but with the downward trend recently, you never know. Keep your fingers crossed.
Hope this answers your question.