Clubs vary in what they expect from members performance.
I am fortunate to belong to City of Norwich AC, which positively encourages new members whatever standard they are capable of running.
The club is currently running a beginners to 5k programme specifically aimed at new and prospective members, which aims to get you up to 5k in around 30 mins in 7 weeks training.
Once you are capable of that, then the improvers group takes over from there with runs of 4 -5 miles, and then a further group with runs of 6 -10 miles.
I'm running with the improvers group.
The road running director also runs the local parkrun, is very supportive and encourages new membership.
Here are the club standards. Its clearly divided into gender and age groups.
I tend to view the standards as a target to aim for on a personal level, I need a set goal or I tend to just plod along rather than push to improve my running.