You'll probably start this topic learning about one of the most important debates in the history of Physics; the nature of light. Is light a wave or a Particle.
Briefly the debate goes something like this, Isaac Newton thinks light is a particle, a corpuscle, science was happy with this, after all Sir Isaac Newton was a pretty smart dude! But science knew there were things that this particular (ha ha ha) model couldn't explain.
Thomas Young, (of Young Modulus fame), comes along two hundred years later and his double slit experiment shows that light can do interference! Amazing, this is definitely a wave behaviour... light must be a wave.
In the early twentieth century Hertz and Planck were looking at a phenomenon that couldn't be explained using wave theory. This is the photoelectric effect! It puzzled them! It took Albert Einstein to get involved with the problem, he gave us Einstein's photoelectric equation. Light must be both, a wave and a particle!
Quantum is your first excursion into Einsteinian physics, enjoy it, but it can get very tricky at times, so take your time, and take Richard Feynmann's advice "If you want to understand quantum mechanics, just do the math. All the words that are spun around it don't mean very much."
And that's solid advice for most of Physics to be honest! :-)