Obviously, who can join is at the group-runner’s discretion, they may or may not prefer to set a level of experience, that’s their right to do.
The 3-month rule doesn’t bar participation because it’s a give-and-take scenario, and actions in the group are witnessed by those taking part, which rules out most concerns.
The rule is primarily intended to keep scammers from abusing free readings and also, give members time to get to know someone before accepting a free reading where they may be revealing personal information.
However it does apply to the person overseeing a group like this, as that would be perfect cover for a scammer, troll, or other blowhard to mess with members.
If we let it start to slip or give exemptions, we open to accusations of favourtism and special pleading and make the rule unenforcable, so this is why i specify these details.