If you press on the fruit and it gives a little bit with a small dent to the fruit, it could be ripe and ready to be eaten, even if it hasn't fallen off by itself. Or at the least, you can take it off and let it ripen a few more days inside your home, instead of letting it fall to the ground.

As for the seed, if the fruit fell to the ground from natural maturity, then the seeds are most likely viable already. You can tear into the fruit to eat (or not) and wash and save the seeds for the next planting.