Guilt is a somewhat useless feeling.  It makes people feel bad for not doing things they don’t want to do.  It makes people feel bad for doing things they want to do.  I person who’s ethics line up with their desires will eschew guilt when they take actions in line with their desires and ethics.  A childfree person might find some conflict, they might feel pressure from outside ethics that say it is a moral mandate to have children.  A person who caves to the first glimmer of guilt and does not stop, reexamine their ethics and put their desires and actions in line with those ethics, will fall further and further into guilty feelings.  First you cave in and have children, then you cannot or do not care for them as is best and you feel guilty, and so on.  The same people who pressured you to have kids against your will might even pressure you to raise them a certain way, and so on.  Don’t let guilt control you.

Stop all the guilt at the first glimmer.  Remember why you are childfree, because it is in line with your ethics and desires.  We all have our individual reasons.