I think it's just a matter of time until he grows old enough. Watch for fighting...Can he get away from her in your tank? Hide in caves or behind wood or fake plants? I have never bred sevs but new world cichlids are pretty similar in breeding behavior.
Then, if they do spawn, do you have a plan? They'll likely care for fry for a week or 2 if they don't eat the eggs. Sometimes it takes a few tries. But most want to breed again (& again), & fry care will stop. It's very difficult to raise even a couple fry in a community tank. You might just enjoy the breeding & not worry about saving any fry...