NI Credits for Parents

My daughter was born 4 years ago however we didn't claim child benefit because I am a high earner. My wife didn't work at the time so she was not getting National Insurance credits for her state pension. She did not know that she could claim child benefits and opt to not receive the payment just to get the NI credits for her state pension in the future. Can she now apply for the NI credits for those previous years when she was not claiming child benefits? Thanks,

Hi ntuleimat,
It may still be possible to apply for NI credits using form CF411A available via this link,  Apply for National Insurance credits if you’re a parent or carer – once received they will check your eligibility.  
It will also be worth contacting Child Benefit to register for CHB without receiving the payment and ensure credits are received going forward.
Thank you.