There’s a first time for everything
Definition 1 of 1
Pro Tip 1/3Encouragement
This phrase is often used to encourage someone to try something new without fear. 
You've never eaten sushi? Well, there's a first time for everything!
Pro Tip 2/3Milestone Events
It can refer to significant first experiences that are often remembered as milestones. 
His first step was shaky, but there's a first time for everything, and now he's running everywhere!
Pro Tip 3/3Optimism
This phrase conveys a positive outlook, suggesting that being new to an experience can be exciting. 
I'm nervous about my first day of work, but there's a first time for everything.