Yes. Only You groups are treated like any other group in OurCal, which means they require a subscription when they’re not covered by a trial or an active plan.
Only You groups are a legacy feature and may not be available to new users. If you already have one, it will continue to appear in your account.
Legacy Only You groups were updated to function like standard groups, so they can be optionally shared by inviting other members.
If you don’t use your Only You group, you can leave it:
Settings → Groups → [Only You] → Leave Group