I don't have kids yet, but I have been to uni, my advice is definitely defer and start on the job training of some kind, and there are loads of short courses you can do, often free, which provide really practical help with training and employment.
University is a massive commitment, it is really designed for women who want to defer having a family untill their 30's, otherwise it isn't really financially viable, a good apprenticeship or short course of some kind is much better IMO.
University was so hyped up when I was at school. So i decided to go, big mistake. I'm now 23 with no savings, lots of sudent debt and little experience in the workforce. I still have to find a job. And I want to start a family soon, so University was probably not the right decision for me

But it does depend on what uni degree you do. I did a degree which wasn't vocational and I didn't really enjoy, so it didn't help with employment very much, it wasn't a good financial move.