This colour wasn't my first choice.

这种颜色并非我的首选。

《牛津词典》

You are my first choice.

你是我的第一选择。

youdao

To tell the truth, this school was not my first choice.

说真的，这个学校并不是我的第一选择。

youdao

You're telling them, "you're my first choice."

你得告诉他们，“你是我的第一选择。”

关于早期入学申请 - SpeakingMax英语口语达人

If I had gone to the college of my first choice, I would not have met my closest friends.

NPR: Ask Amy: Responding to the Thin Envelope

This was not my first choice by any means, but it was at a respected agency, so I thought it was worth a shot.

FORBES: Coming To Terms With Underemployment

The late David Foster Wallace would have been my first choice.

FORBES: The 2011 U.S. Open--Monday Musings