DS will have his birthday party in January. Invitations were sent on 22.11.2024. The RSVP date is 09.01.2024. Can I only chase from that date or can I ask parents the week before they break up for Christmas when I see them during the school drop off/pick up? Or just wait till the RSVP date? This is DS first birthday party, so unsure what the etiquette is. TIA.