Billing/ effective date questions

Hello I am on my parents health insurance as I am 25. I turn 26 in October. I am also getting married on June 24.

My parents health insurance will kick me off at 26 and I can apply for my employers insurance plan. Or I can apply my employers insurance due to my wedding since this is also a qualified life event. Both are the same insurance company but different plans of course.

I am confused because they said the effective date of the benefits would be the day of the wedding.

I get infusions every 8 weeks. One will fall on July 7. The medication would ship before the wedding. Will it cause billing issues if I apply for my employers health insurance after my wedding? Which insurance would the infusion be billed to? I doubt I will have the required documents to apply for the change of insurances until after the July 7 infusion. So how would they approve it? Getting the infusion approved in the first place was a huge hassle and took a lot of time so I don’t want to mess anything up.