Looks like it’s somewhere between a Norwood 2 and a Norwood 3, but can’t tell for sure without a reference pic from when you were younger. As for letting nature take its course, that depends entirely on how important your hair is to you.
Depending on your original hairline, this could qualify as a borderline mature hairline. If that is the case, then the recession should halt in the very near future. Take pictures every 3 months then compare. If it stops, your good to go, if not it’s time to consider treatment.
In the meantime, research treatment methods and take the time to fully consider the value of your hair and how far you are willing to go to save it. This will allow you to immediately begin a regimen should you need to.