That is a frustrating situation - especially in circles where much of the shidduch hishtadlus responsibility falls on parents, when you feel your parents aren't taking on that responsibility, that can leave you feeling disadvantaged.
It doesn't sound like your mother is going to change her perspective. Whether because of her background, her personality, or her experiences with your older siblings - this is the amount of effort she is going to put in. If you feel that more hishtadlus has to be done to be responsible - it is going to be your responsibility, hard as that may be.
Does more hishtadlus need to be done?
Much of our responsibility for hishtadlus does depend on our perspective. If we feel that more hishtadlus needs to be made to give us a reasonable, b'derech hateva chance of getting married - then it does. If we really, honestly don't think more needs to be made (and not because we're lazy, and not because we're fooling ourselves into thinking we have more "bitachon" than we really do) - then usually what we're doing is enough.
From what you wrote, it certainly sounds like you think more hishtadlus should be made. Even from a more "objective" standpoint, if you've only had one date in several years (and you would like more), it sounds like more hishtadlus should be made.
You sound like a person who knows how to take action, and while it may be frustrating to have to do all the legwork by yourself without parental help, it sounds like you'll be able to do so effectively.
The decision is obviously yours to make, but from what I am hearing from you, it seems like from all vantage points - emotional, spiritual and practical - your putting in more efforts makes a lot of sense.
B'hatzlacha - may Hashem put bracha in your efforts!
All the best,