She could be but it's not the most common cause of what you are seeing. At around 6 months of age, they will have their first cycle.
The humping is probably not sexual at all but is her way of exploring her environment. It's pretty common. She might hump towels, clothes, pillows or even you. When she does this, be sure and discourage her.
When she's in heat, you will see swollen labia and bloody discharge.
I would be more concerned about the urination around the house. I think that you should see the vet for a urine culture to rule out a UTI or urinary stones.
Let me know if you still have questions about this.
The licking is probably because she is pretty excited by all the humping. The two usually do go together.
Not an active Expert