Happy to answer any questions about the app or starting strength in general (although I'm not an SSC, I have done the seminar and been strength training for about 5 years).
Here's a bunch of free resources to help people get started:
Starting Strength sub-reddit - Scott Hambrick (a starting strength coach) is active on there and will do form checks and give advice on general questions. https://www.reddit.com/r/StartingStrength/
Speed and power is entirely genetic. you're either fast or not. you can either jump high or you can't. you can improve it but only by slim margins.
Strength however, can be trained and improved greatly and well into middle age, which is why barbell training is so popular.