It depends on who you are.
Typically, females are ready earlier than males because we mature more quickly. However, that is not always the case as I am dating someone who is almost a full year younger than I am, and it hasn't taken away from our connection in the least. I see the fact that you are seeking out answers before making your decision a sign that you could be ready. And from the sounds of it, you aren't interested in dating just to be "cool." However, you know yourself better than I do.
Keep in mind, that sometimes your heart has different ideas than your brain. My mother started dating before her mom said she could. I thought the earliest I would ever date is now (halfway through 8th grade), but I've been in a relationship for 8 months. Chances are, if you really like someone, you aren't going to wait for a specific age. I didn't even really consider my maturity or his that much when I told him that I like him, and later asked if he was ready for us to become something.
It also depends on the intensity of the relationship. Some people seek a connection on a deeper level, others do not. Some don't seek it out, but find themselves in a deep relationship anyway. You might prefer to start out smaller, and that's okay. Typically you need to be more mature for deeper relationships, however a lot of the time, you don't consciously choose that either. It just sort of... happens.
In short, follow your heart. Analyzing everything isn't always the best way to go, because you will most likely not follow your plan. Hardly anyone does.