25-30 mpw is quite low mileage, but a 19:35 5 k is decent for this volume.
Mile time is not so much affected by this, it depends more on basic speed and lactic acid tolerance.
When I was a young beginning middle distance runner at about 16 yo and ran my very first mile race at 4:54 (a real 1609 m) I was not faster than 18:45 for the 5 k, but had a 12 s FAT 100 and a low 2:0× 800.
I soon progressed to even sub 4:40 in the same year (converted from a 4:18 1500). It was not connected to mileage at all, maybe 30, definitely less than 40 mpw even at winter base training at that time. While the 3000 was still ok with just a sub 10, the 5 and 10 k sucked with 18:45 and something around 41.
Of course I had a good progress in the longer distances, too, with higher milage later on.
However, middle distances like the mile are not necessarily comparable to 5 k times and strongly dependend on body composition, type of training, basic speed, power and lactic acid tolerance.
You seem to have some talent for the shorter distances, but it might be difficult to find adequate races at your age.
If you like to improve the longer distances, training volume and consistency (high mileage and no interruptions due to injury and the like) are key.