第一印象很重要。

First impressions matter.

Source: Tatoeba

Sentence Composition

=1 第一 dìyī
  1. first
  2. most important; primary; foremost
=1 第一 dì-yī
  1. (literally, figuratively) first; 1st
  2. being the most important consideration; being essential, or a priority; coming first
  3. first; 1st
  4. firstly
  5. number one; #1; first (in a test, competition, etc.)
2 印象 yìnxiàng
  1. impression (sth that stays in one's mind)
  2. a memory
3 很 hěn
  1. very; quite
  2. (also, often used before an adjective without intensifying its meaning, i.e. as a meaningless syntactic element)
4 重要 zhòngyào important; significant; major