@WojciechWB my apologies, I didn’t formulate my previous answer correctly. Calculation properties will either only count (rollup) associated objects (contacts, deals, tickets, companies, custom objects) but as of now, associated activities cannot be referenced. Unless the information about the activity is stored in a contact property, it cannot be accessed as part of calculation.
As far as workarounds go, here’s what you could do:
- Create a workflow that enrolls records when they’re associated to a meeting, then logs the current date in a custom date property (the main downside here is that the workflow won’t know whether it’s the first meeting and that this won’t work retroactively)
- [Operations Hub] Use a custom code action and leverage the Engagements API to look up the date of the first associated meeting and log it to a custom date property
Outside of that, there might be marketplace apps or third-party automation (e.g. Zapier) which might help accomplish this.