I'd like to see the updated videos. Based on what I see here, I can suggest to try to get a little lower during your approach. You want to generate power through your core/lower body. In this video, you are leaning forward at the line and losing a lot of momentum. I've only been doing it a few months, myself - and I'm more than twice your age - but I've quickly discovered that the power comes from the lower body. And any lean forward kills it.
Also, and this is likely due to your forward lean, it appears you are coming around the ball too much. This is also killing speed and revs. Throwing 2 handed, you will find the most powerful shots by staying behind the ball and driving through it. It will help get the ball down the lane and retain energy for the backend. When done correctly, you will see a big difference in pin action. If you watch Belmo and Osku videos, you will see what I mean.
The good news is, you are still young. Hopefully you can find some coaching to help you out. I've mostly had to do it on my own, but I've managed to become pretty good at it in a short period of time (though still far from mastering it). In fact, during rock and bowl league last night, several people (including a teammate), were shocked when I told them I had only been doing it for 3 months, plus a bit last summer. I shot my high series last night of 686. Only 2 opens and one was a 7-10 split. It took me a little while to get a 600, but in March I've had 10+ across 5 leagues. In the last 2 weeks I have shot 650+ twice in two different leagues. I feel like this is the way I was meant to bowl.