diff --git a/src/BusProNet/XmlParser/BookingParser.php b/src/BusProNet/XmlParser/BookingParser.php
index 00217a1..553e919 100644
--- a/src/BusProNet/XmlParser/BookingParser.php
+++ b/src/BusProNet/XmlParser/BookingParser.php
@@ -116,8 +116,7 @@ class BookingParser extends AbstractParser
         $personalData->mutable = $this->getBoolValue($node->filterXPath('//aenderungmoeglich'));
 
         $dateString = $this->getStringOrNullValue($node->filterXPath('//geburtsdatum'));
-        $personalData->dateOfBirth = null !== $dateString
-            ? \DateTimeImmutable::createFromFormat('d.m.Y', $dateString) : null;
+        $personalData->dateOfBirth = $this->stringToDate($dateString);
 
         $personalData->firstName = $this->getStringOrNullValue($node->filterXPath('//vorname'));
         $personalData->name = $this->getStringOrNullValue($node->filterXPath('//name'));