Store in an air-tight container in the refrigerator. While I do not advise it, I kept mine for as long as 2 years in the refrigerator and it was still delicious, though a little brown in color.
*Some makers of rum age it in barrels that were previously used to age whiskey. If you are extremely sensitive to gluten (cannot tolerate the allowed less than 20 parts per million), you should avoid such brands of rum. Check with each manufacturer.
I used overly ripe bananas and it still turned out very well. If your bananas are brown, the color of the liqueur may be a little darker/tanish yellow.
https://glutenfreerecipebox.com/gluten-free-banana-liqueur-recipe/