How do you know if you have type 1 diabetes?

See your doctor. You need a blood test to get a diagnosis. Sometimes diabetics can experiece, blurred vision, numbness or tingling, feeling hungryor thirsty all the time, frequent urination, or frequent infections (ear or yeast for example).
For you ? At a listed age of 47 it is very unlikely you would suddenly develop T1DM, since it peaks in pre-teens. At your listed age T2DM would be more likely. The kids usually present acutely ill, loose 5-10 lb in a week and have been eating and peeing continuously. Adults with T2DM can go years without symptoms& without diagnosis. Having your blood sugar tested under specified conditions can sort this out.
Drinking, urinating. Earliest signs are drinking a lot ( polydipsia) and "peeing a lot" ( polyuria) As the blood sugar continues to rise, tiredness, headache, malalise, weight loss, dehydration set in. If not caught at this stage, insulin deficiency will progress to comatose state. Buy a walmart glucometer and 9$ strips and check your blood sugar. It should not be over 100.