Hello,
Apart from pregnancy, there are many other reasons for a delayed period. The other causes are hormonal imbalance like in PCOS (Polycystic ovarian syndrome), stress, obesity, malnutrition, anemia, hypothyroidism, illness, etc. The only way to know whether you are pregnant is to get a pregnancy test done. You can do a home pregnancy test by using a pregnancy kit easily available at chemists. Also, it is suggested that you see a gynecologist who will examine you.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
Your still young and sometimes its normal, but if your planning a baby you should seek a doctor pregnancy tests can skip certain unique hormones you have that are pregnant ones, go to a doctor
Im far from an expert on pregnancy tests, but I dont think home tests are 100% correct. I believe blood tests are advised to determine if you are pregnant, they should be much more accurate than home tests. Good luck :)