AZ:
People without money will be left out (and unwilling to try, due to lack of funds), even at a younger age. We already collect for the 28 year olds, are you ready to collect for the 19 year olds? Many parents can’t afford 150$ to “take a chance”, which can be multiplied 20 to 30 times (possibly) per girl.
A better idea would be for the community to pay a shadchan full time to work in a community, with tips/bonuses allowed? for successful shidduchim (similar to what has been done in the Five Towns area). This way the shadchan will work for everyone, not only those who can pay the “entrence fee”.