We use olyan before an adjective to mean "...as...as...".
Ági olyan okos, mint Einstein. Ági is as smart as
Of course we can use nem too, to mean "not as ... as ...":
Angelina Jolie nem olyan szép, mint Ági.
Angelina is not as pretty as Ági.
N.B. here, mint means as, not than.
We cannot use the -nál/nél
suffixes in equality statements, only in comparative.
for more details of mint and -nál.