I'm really sorry to hear that you are feeling like this right now. Navigating these emotions must be really overwhelming for you but it's important to know that you are not alone.
I agree with Sophie_M and White Rose that you might find support offered through the Beyond Blue support service and Kids Helpline useful and comforting. I would also recommend contacting Headspace or your local GP to get a mental health care plan for long-term support with your anxiety.
You asked if 17 years old is a normal age to experience what seems like symptoms of anxiety. Anxiety doesn't discriminate and humans can experience feelings of anxiety at any age. There is absolutely nothing wrong with you :)
Please let us know what you choose to do