How does an SR Latch get started
It is true that the latch will "wake up" in an unknown state. In the real world, given a little time, the latch will have a valid state with either Q=0 or Q=1.

You make the latch "get started" by setting one of the inputs (R or S) to be a 1 while the other input is a 0. This will force the latch into a known state, regardless of whatever the previous state of the latch might be.

In other words, if you want to know the state of the latch then you must explicitly Set or Reset the latch.