That was a great first shave!
Dittos the blade sampler. You need to determine what blade(s) work best for you: Eventually. Right now you have a lot on your plate so find a blade and stick to it to get everything else working right. Sounds like you decided on the Feather. That's not a bad thing. By using that blade you'll learn rapidly. It beats using a junk blade. Feather makes a fine blade- it's definitely sharp enough so that won't be an issue. If it starts to drag or pull the skin, change it.
Lather is one of the keys to a great shave, so concentrate on that, and forego, for the moment only, a close shave. Lather needs to provide lubrication and cushion. Make a few test lathers so that you can see how the soap lathers. Don't plan on shaving with these, just make them and waste them down the drain. Bring the lather to the point you think is right for use. Lather your arm and see how long the lather remains useable. Add more water and test along the way. Continue doing this until the lather breaks and starts to become foamy. That'd be no good to shave with, but you need to know what that sort of unuseable lather is and where the lather is best. OK, so you're lathering your arm... you need to know how long it lasts so that you know how to proceed with your face; applying it, and how long you have to shave before it becomes unuseable. Does that make sense?
Remember, if you have lather problems there are few problems that can't be cured by not using more product.
It sounds like your doing OK though.
FWIW, the 30 degrees is just an approximation. Razors work differently and eventually you'll forget the 30 degrees and just use the angle where the razor works. You'll figure it out.
The other key is "no pressure". I taught my buddy to blade shave and told him as we all tell every newbie, to use "no pressure". A few months after beginning he called me one Saturday and told me, "When you say 'no pressure' you really mean no pressure don't you!?". It finally sank in and he used just the weight of the razor and got his best shave ever, no irritation, no blood, just a great shave. OK, so "no pressure" is an oversimplification, you must have some, but it's infinitesimal pressure. Just enough to keep the razor from chattering. I use the light grip as the shock absorber to remove the chattering and that pretty much does it for pressure for me. If your skin deforms as the razor passes over it, that's too much pressure.
Eventually you're going to want to change things. Resist that for now. Keep all potential variables static and learn the basics. Get them down. Then when you have it down pat, change one variable at a time. If you change more than one you'll have no idea what variable had what effect. Eventually you'll know what variable did what, but as a beginner keep it simple, learn the basics and you'll get up to speed much quicker than if you just start to change things at random.
Oh, and keep notes. Especially when you're to the point of trying the different blades in a blade sampler. If the sampler is large, and I suggest the largest sampler you can find, you may not remember the nuances of each blade. Keep exhaustive notes. I'm in my 10th month of my foray into blade shaving (this time, first time was in '69/'70) and I'm still testing blades. I have very high standards for what I'll accept and I have exactly 3 best blades (double edge) out of close to 30 tested. If you have a small sampler you may miss your best blades.
Don't get rid of your sampler either. If you get a different razor you may need it to find a best blade for that razor. BTW, that's one reason why I have so few best blades. I want to simplify things by buying blades that work great in all my razors. That takes time and raises the bar for all the blades.
I didn't intend to write a book, but it happens when I get to the keyboard. You'll do fine and we're here when you need us.
Maker of Kramperts Finest Bay Rum and Frostbite http://www.krampertsfinest.com/
Or find it at Bullgoose, Italian Barber, and West Coast Shaving. Brick and Mortar: The Old Town Shaving Company at Stats, in Pasadena, California