kaiajosephine, I am not sure how you figure that you are having problems? You sound pretty normal.
"I heard that it's hardness can change depending on where you are within your menstrual cycle" - This is indeed correct. It is soft when you are fertile, hard when you are not fertile. It is low in your vagina (easy to feel) if you are not fertile, high when you are fertile. It will have a little closed hole in the middle when you are not fertile, and a more open hole when you are menstruating or fertile.
Cervical mucus comes out of it when you are fertile and menstrual debris when you have your period. Sperm goes in there when you have unprotected sex and babies comes out of it during natural childbirth.
It can point down or slightly to the back (normal) or point towards your belly when your uterus is retroverted.
It can be pleasurable when touched or extremely sensitive and sore if it is touched.
During arousal it will move as your uterus rise in your body cavity.
During orgasm, you can have contractions running up your cervix and into your uterus. Your cervix will also move around when you orgasm.
Your vagina is a closed tube. When unaroused the walls are flat on top of each other. When you get aroused, the wall will open up and lubricate. At the top of your vagina you will feel something like the tip of your nose. This is your uterus. When it is stiff, it is stiff like the tip of your nose. When it is soft it is soft like your lips.
Remember to wash your hands and groom your fingers before poking around in your vagina. Although it is a closed 'tube' and there is nothing you can damage or push up into your insides when you poke around there, you can get a yeast or bacterial infection and you can scratch yourself.
Feel your cervix every few days to track its changes across your menstrual cycle. Also take a mirror and look at your genitals. The more you know about your own body and how it feels, looks and reacts, the better you can protect your own health in future.
Take care!