I am 20 years old and I checked my blood pressure yesterday and it was 154/85 and they said its normal but my mom says its high. Should I be worried??

Don't worry but see. A single blood pressure of 154/85 may be completely normal especially if after exercise, stress or excitement. Do others in your family have high blood pressure? If you find the top number is higher than 150 at rest on repeated checks, then see your doctor. Be sure that the device you use to measure your blood pressure is working properly.
Yes. recheck it please probably see another opinion if readings constantly stay the same may need attention ,If there are fluctuating reading then it might be normal variation and will not need treatment.