Hi, Kieran —

Thanks for the question.

You said:

• If someone has been living a life of sin since they were a child and has decided to seek forgiveness and start living as a Christian, if they repent and go to Confession but cannot remember all their sins, are they still forgiven?

Yes, they are.

Any Catholic who goes to Confession and does their best to remember all their previous sins, are absolved of all their sin:

• if they are truly sorry, and
  
• strive to not commit those sins again to the best of their ability
  

If you are a Catholic in this situation, there is nothing you should hide from the priest as he has heard everything. Hiding sins only hurts you.

A non-Catholic Christian cannot receive the sacrament of Confession except in case of emergency.

In that case, they should:

• ask for forgiveness in the heart (by saying a prayer.)
• seek Christian counseling if there are sins of a habitual nature, and
• strive not to commit those sins again.

Mike