Get_post() with meta_key when compare is a date

I think you have error in your query. Please try this:

$posts = get_posts(array(
    'post_type'         => 'events',
    'posts_per_page'    => -1,
    'meta_query'        => array(
        'meta_key'          => 'from_datetime',
        'type'              => 'DATETIME',  // You can also try changing it to TIME or DATE if it doesn't work
        'meta_value'        => date( "F d, Y g:i a" ),
        'meta_compare'      => '>',
    ),
    'orderby'           => 'meta_value',
    'order'             => 'ASC'
));