why do আপনি think princess পীচ is the main princess?

Because she is pretty and girly and better than daisy

because নিন্টেডো made her before ফ্ুলপাছ অথবা rosalina and plus she the princess of the মাশরুম kingdom :)

because she has mario who rescues her about each day.

Because Shigeru Miyamoto created Princess পীচ to be a part of the main cast.

ফ্ুলপাছ doesn't get the same luxury because Super Mario Land was made without Miyamoto's knowledge. (Or so I was told.)