"a month" doesn't say much. To be honest, when a player first unlock the feature, they are probably in the stage at which they don't have a lot of coins, so for all we know you could have put in rather minimal amount of coins.

What is your training point thus far?

On average, you'd get a red for every 20k or so training point and a gold for every 10k or so. This is average thou, and law of large/small number dictate that you will only be reasonably close to the average once you get to at least 10 times that. For your first one, you could get it very early or have a decent chance of not getting one until 3 times the amount or so.