Kissing is not a risk of HIV. You will only get HIV from unprotected sex or sharing IV needles, nothing else. So delayed sero cannot be an issue for you as you never had a risk of HIV. But you the record, delayed sero will only happen and even this is very rare indeed if your on medication for a new organ, or been using IV drugs for many years or aggressive chemo.
So, to confirm, you had ZERO risk of HIV and you have nothing to worry about