Oh goodness, @Loosingitbitbybit
I had children by the time I was your age, and was posting smug crap on MN (when it was all fields, and I was one of about two posters) about why everyone should be a SAHM.
I never imagined, then, that I would end up divorced, 48, and unemployable.
So I suppose I would say to my 28 yr old self: take this opportunity to re-qualify as the thing you would most love to be (I am super-highly qualified, but in a field in which I have no interest or, now, experience). If that's not possible, qualify in a way which means you could go back to work to support yourself and your children, should you need to, however unlikely it sounds now.
I would also tell my 28 yr old self that my small children will not die/fail to bond with me/lose out in any other way if I am not with them 100% of the time, every single day. In fact, they would be ok at pre-school for a few hours a week, if it meant I could give myself (and, therefore, them) more options in the future.
I would also advise myself to sort out a pension, because I am nearly 50 and don't have one.
I would also advise myself not to marry my XH, but hindsight gets us nowhere. In the event, actually marrying him (as opposed to living together and having children) is what has saved my financial bacon. But it would have been better to have married someone who turned out to be nicer, and to have had children with him instead.
Finally... your relationship with your partner and children will be different from your relationship with your parents. My parents were the absolute best, in every possible way. We were the closest family, laughed endlessly, etc. They created this from dysfunctional upbringings. My children, however, have had a dysfunctional upbringing, even though mine was brilliant.