PHP, 104 88 bytes

for(;$i++<$argn;$a.='**',$i++>1?$o=$s.$o:1)$o.=$s=str_pad("*$a",$argn,' ',2)."
";echo$o;

Try it online!

This doesn't beat the lowest scores for PHP on this challenge, but it's just too crazy for me to throw away.

Okay, so I've golfed now it to be the lowest score for PHP on this challenge, but it doesn't change the fact that it's still crazy.

$ echo 7|php -nF hour.php
*******
 *****
  ***
   *
  ***
 *****
*******

PHP, 104 88 bytes

for(;$i++<$argn;$a.='**',$i++>1?$o=$s.$o:1)$o.=$s=str_pad("*$a",$argn,' ',2)."
";echo$o;

Try it online!

This doesn't beat the lowest scores for PHP on this challenge, but it's just too crazy for me to throw away.

Okay, so I've golfed now it to be the (not for long) lowest score for PHP on this challenge, but it doesn't change the fact that it's still crazy.

$ echo 7|php -nF hour.php
*******
 *****
  ***
   *
  ***
 *****
*******

PHP, 104 88 bytes

for(;$i++<$argn;$a.='**',$i++>1?$o=$s.$o:1)$o.=$s=str_pad("*$a",$argn,' ',2)."
"?><?=$o;

Try it online!

This doesn't beat the lowest scores for PHP on this challenge, but it's just too crazy for me to throw away.

Okay, so I've golfed it to now be the lowest scored PHP on this challenge, but it doesn't change the fact that it's still crazy.

$ echo 7|php -nF hour.php
*******
 *****
  ***
   *
  ***
 *****
*******

PHP, 104 88 bytes

for(;$i++<$argn;$a.='**',$i++>1?$o=$s.$o:1)$o.=$s=str_pad("*$a",$argn,' ',2)."
";echo$o;

Try it online!

This doesn't beat the lowest scores for PHP on this challenge, but it's just too crazy for me to throw away.

Okay, so I've golfed now it to be the lowest score for PHP on this challenge, but it doesn't change the fact that it's still crazy.

$ echo 7|php -nF hour.php
*******
 *****
  ***
   *
  ***
 *****
*******

PHP, 104 bytes

for(;$i<$argn;$a.='**',$i=$i?array_unshift($o,$s):1)$o[]=$s=str_pad("*$a",$argn,' ',2)?><?=join("
",$o);

Try it online!

This doesn't beat the lowest scores for PHP on this challenge, but it's just too crazy for me to throw away. Enjoy.

$ echo 7|php -nF hour.php
*******
 *****
  ***
   *
  ***
 *****
*******

PHP, 104 88 bytes

for(;$i++<$argn;$a.='**',$i++>1?$o=$s.$o:1)$o.=$s=str_pad("*$a",$argn,' ',2)."
"?><?=$o;

Try it online!

This doesn't beat the lowest scores for PHP on this challenge, but it's just too crazy for me to throw away.

Okay, so I've golfed it to now be the lowest scored PHP on this challenge, but it doesn't change the fact that it's still crazy.

$ echo 7|php -nF hour.php
*******
 *****
  ***
   *
  ***
 *****
*******