Hi and welcome to the music stack exchange. The short answer for you is, yes that is a form of the traditional grip
also known as orthodox grip or conventional grip and, to a lesser extent, the jazz grip.
The longer and somewhat less convenient answer is that you could still be "doing it wrong" potentially... there are correct and incorrect ways to strike a drum with this grip. You can be holding the stick incorrectly still. And, you may or may not be playing with too much tension in your wrists and/or fingers.
This really isn't the place to ask in the sense that no one here can examine how you are implementing the technique... You could potentially post more pics and a video of how you are playing in order to get a little better feedback. But, you are much better off to get one or more lessons on rudiments before proceeding with techniques that you are unfamiliar with. At very least, do some Youtube research to help get you started:
Any grip is a fulcrum, and the most important part is to grab the stick well, usually with index finger and thumb, as in the picture. That is the balance point of the fulcrum. And this applies to traditional, matched grip, and every grip. You should have it with pressure, it also will give you information on how is vibrating the stick.
I recommend you to master first the matched grip, as it is more natural. People who play traditional grip don't do this because they are good players, they do because the instrument needs it. The situations when you need the traditional grip are when playing in a marching band and the drum is not horizontal and when playing with brushes.
In a traditional grip you should grab well the fulcrum, with index and thumb. Between 3/4 and 2/3 of the lenght of the stick, where you find the balance point of the fulcrum. The stick lays back between the middle and ring finger.
There is a lot of work when mastering any grip, you should do exercises with fingers, with smaller sticks, in a lot of positions to make the fulcrum work.