now there is no actual device to test if you are really in love and it will last forever, so that's why elders prefer not to for love marriage as most of the time it just fades away with time hence the marriage breaks, and if it breaks eventually it is you who will be hurt the most.
just my thoughts! i am no expert or guru here :p
love marriage kar lijiye
elders may be right but its ur life,, learn to take ur own responsibilities