Hi Asjad,
Their age difference isn’t that much. However, I do not recommend pairing lovebirds and setting them up for breeding until they are about 2 years old. They will breed at their current age, but they are really not ready. They still have some physical development going on, but more importantly they are not ready mentally. They are immature and more interested in mating and playing than settling down to care for eggs or chicks. Some young males will end up not helping and may break or eat the eggs so the female will mate with him again. Some females will also ignore the eggs or break or eat them. If they develop bad habits, they often will never be good as breeding birds. Young females are also at a higher risk of becoming egg bound and dying. If you let them finish growing up, they are more likely to be successful at mating and she will have an easier time of laying the eggs. And both are more likely to settle down and sit on the eggs and then care for the chicks.
I would spend the next year getting them into good condition. I would not put them in the same cage yet. Give them some toys and let them play and exercise and get all of that our of their system. Feed them a balanced diet like pellets – not a loose seed mix. Also offer dark leafy greens, chopped veggies and some fruit. They need to be on a good diet like this in order to produce healthy chicks and to remain healthy themselves. In the end it will be worth waiting because they should be a better breeding pair than if you start them too young.
Thank you for asking Lafeber,
Brenda