Dear Shtark Bais Yaakov Girl,
Not everyone has the same מצוות.
Just as men and women have different מצוות,
Leviim have different מצוות than Yisraelim,
and Kohanim have different מצוות than Leviim.
Kings have different מצוות than commoners.
Some מצוות only apply to a prophet [Navi].
Some מצוות only apply in Eretz Yisrael.
Some מצוות only apply every 7 years or every 49 years.
Some מצוות only apply during the day or night.
Some מצוות only apply on specific days of the year;
Shofar is only on Rosh HaShanah.
Fasting is only on Yom Kippur [and a few other days].
To what can this be compared?
Soldiers who fight on dry land have different orders than sailors who fight at sea.
Members of the Air Force have different orders than sailors.
Spies who collect information about enemy soldiers have different orders than sailors.
Some members of the military spend all their days working
to decipher the secret codes of the enemy army,
so they can understand what the enemy army plans to do;
they also have different orders, and their work
may be done very far away from the fighting.
Even within the Army, some soldiers specialize in making food for other soldiers,
or specialize in distributing supplies, such as: uniforms, shoes, blankets, and soap.
The Army also has Doctors and Nurses and surgeons, who do not fight.
I hope this helps you.
I wish you only good decrees on Rosh HaShanah
and a very easy fast on Yom Kippur.
Sincerely,
SQUARE_ROOT