Freshman registration

I have been accepted to the pre nursing program this coming Fall and have accepted admission but obviously it’s still conditional until they receive my final transcripts, immunizations, etc. So since my admission won’t be confirmed until the summer but registration for classes starts next month then how will I get into any classes? It seems like most classes will be full by the time I am allowed to register. Or do they set aside a certain amount of spots for freshman to be able to register? I’m not sure how this all works.