Alex164...
No point in a teen taking creatine. Is it safe? Debatable. I don't think there are any known cases of creatine and teens having adverse affects but at 15, you'd be better off just going for the basics. Wait until you are 19+ to start things that may or may not affect growth and development. I'm not even saying creatine will do that but just be safe. You won't get that much gains out of it at 15 anyway. But you will with diet and training. At 15, I can only assume diet is something you need help with to refine and really work on?
What does creatine do? A topic of the bonus books I have with my own Beginner's Guide and a small bonus for becoming a DB member.
But in a nutshell, it helps with ATP, so you have more energy to push more weight, to get stronger to get bigger. Creatine itself, does not build muscle.
Whey protein with water, if it's a good brand will be fine. I mix with water all the time with my Muscle Milk and it's great. But I've had stuff that tastes just okay with water.
There are several brands.
Muscle Milk by Cytosport if you want the good stuff
Optimum if you are on a budget
If you are planning on going to a store, you outta check out
Supplements101 You might save a lot of money
And you will help support DB