Credit went down from apartment application a high amount

I’m 21 years old, been slow building credit, not too keen on finances while I start my life up a little behind

Today I noticed that a new apartment I co-signed with my parents and grandma did a hard check on my credit. And it dropped my credit by 45 pts

I’ve checked some posts and seen people complain about hard inquiries dropping 4-5, but going from 731-686 when I’ve never had any bad credit history seems very extreme

Is this normal for a hard inquiry? Is it due to my young age signing up for a lease on an apartment ?