Well they're both young so that's a good start.
When introducing them do it in a neutral area. Some people do it in a small tank or cage, some in a big play area, but if it's somewhere neither of them has been before they won't be territorial over it so they shouldn't fight.
Put them in each other's cages and let them share dust from the dust bath. Give it to one then the other. Swap toys from one cage to another, things like that so they get used to each other's smell.
What I did with mine was hold one of them by the open door of the other's cage but hide his head. The female would then groom his back and after a while I let his head out so they could groom each other.
They will probably fight a little bit, but you must decide when it's getting too rough. A bit of fur will fly as they decide who will be the dominant one, but if you see any blood of if you think one of them is bullying the other or if one looks too distressed, separate them and don't try again for a few days. If it's too bad don't try again at all. Chinchillas can kill each other.
You know your chinchillas so just take it slowly and always supervise them. And good luck.