20+ years ago, and I definitely would not have consented to shit then that I love now.
Yes, but past you did consent to shit back then (loans, etc) that affect you today, whether or not you love it. So what's the difference if the timeline is reversed?
No. This has been brought up and debunked by experts. Despite the rapidly falling birth rate, it will take centuries to overcome population inertia. Changes will not happen anywhere close to fast enough to save us from the environmental crisis we are facing. If anything, it may make things worse as an aging elderly population means the young generation is preoccupied trying to take care of them instead of dealing with the shit they left behind.
Our ideal birth rate would be between neutral to very gradual decline, not the cliff jump we're currently facing.