title: date-fns Format Date and Age calculation problem in React
body: <p>I was using &quot;moment.js&quot; in my project (like age calculator), but I want to replace it with &quot;date-fns&quot;.</p>
  <p>Using moment.js, I formatted the input value as DD / MM / YYYY (for TR) and was calculating the age by subtracting the current date but right now I am having trouble doing this with date-fns. I felt like moment.js came easier to use.</p>
  <p>Moment.js age calculator codes: I entered the input on <strong>10/03/1998. (DD/MM/YYYY -&gt; Turkey)</strong></p>
  <pre><code>const birthDay = moment(value, 'DD/MM/YYYY');
  console.log(birthDay); // (output: 10/03/1998)
  const now = moment();
  console.log(now); // (output: Thu Mar 04 2021 10:40:09 // TR Local Time)
  const age = moment.duration(now.diff(birthDay)).years();
  console.log(age); // (output: 22)
  </code></pre>
  <p>I tried to do it with date-fns but was not successful. I can not calculate the age.</p>
  <pre><code>const birthDay = format(new Date(value), 'dd/MM/yyyy');
  console.log(birthDay); // (output: 03/10/1998 - **issue 1**)
  const now = new Date();
  console.log(now); // (output: Thu Mar 04 2021 10:45:18 // TR Local Time)
  const age = differenceInCalendarYears(now, birthDay);
  console.log(age); // (output: NaN - - **issue 2**)
  </code></pre>
  <p>I would appreciate it if you could help with date-fns.</p>
  <p>I edited for the answer, right now it's like this:</p>
  <pre><code> const birthDay = new Date(value);
   console.log(birthDay); // Oct 03 1998 (03/10/1998) it's MM/DD, I want DD/MM
   const now = new Date();
   console.log(now); // Mar 04 2021
   const age = differenceInCalendarYears(now, birthDay);
   console.log(age); // it should be 22 but 23.
  </code></pre>