Use core modules where available. Your subroutine doesn't handle the different month lengths or leap years and besides, is wildly inaccurate (the epoch began at 1970-01-01 00:00:00).

use strict;
use warnings;
use feature 'say';
use Time::Piece;

my $timestamp = '2025-01-12 09:30:00';
say "Timestamp     - $timestamp";

my $tp = Time::Piece->strptime($timestamp, '%Y-%m-%d %H:%M:%S')->epoch
+;

say "Time::Piece   -  $tp";

sub timestamp_to_epoch
{
  defined $_[0] or return 0;

  my @T = split(/\D+/, $_[0]);
  return $T[5] + $T[4] * 60
    + $T[3] * 3600 + $T[2] * 86400
    + $T[1] * 2678400 + $T[0] * 32140800;
}

say "Harangzsolt33 - " . timestamp_to_epoch($timestamp);
[download]

Output:

Timestamp     - 2025-01-12 09:30:00
Time::Piece   -  1736674200
Harangzsolt33 - 65088869400
[download]