I think you need to consider that a lot of us are speaking from experience - difficult childhoods (mine was also extremely abusive) mental illness, struggles with friendships, lack of support while pregnant/as a new mum...
Setting that aside though my advice would be:
Do ALL you can to get as physically and mentally healthy as you possibly can! This could involve several more years of therapy, physical training, overhauling your diet...
An unexpected thing I struggled with was giving up caffeine! I had no real idea how much I was consuming as it was very much habit, following my 2nd mc I did some research and learned that caffeine is really not good for pregnant women and at the very least consumption needs to be minimal. I quit cold turkey without fully appreciating how addicted I was and felt very very unwell and didn't know why! Thought I had flu or something. Luckily gp quickly recognised and advised to wean off slowly which I did and I've never gone back to that level of consumption because I never want to feel that lousy again!
There are also certain foods and food additives that aren't advisable during pregnancy, with my experiences I decided to cut those out of my diet as soon as I stopped taking the pill so about a month before actively ttc again, and again I very much noticed I felt pretty rough initially (and even with those items I was eating a much healthier diet than most at that point anyway which I think goes to show how we're eating stuff we don't even realise is bad for us)
It's also a really good idea to build up your stamina significantly - both for pregnancy and labour and the early years of parenting. I have a lot of experience with babies/children and was a nanny before having dd but definitely still wasn't fully prepared for sleep deprivation or the relentlessness of it all.
Build a support network - friends don't have to be people your age/background - some of my closest friends are much older/younger than me and from very different backgrounds, you'll meet a wide cross section of people at uni especially if you make an effort with the extra curricular stuff (which is generally very good for your cv too)
Learn all you can about baby and childcare - there's a lot of focus at the ttc stage on pregnancy and childbirth and it's very easy to forget there's actually an extra person to care for at the end of it all! I had my own "Ross from friends" moment around 7.5 months pregnant of "oh fuck! Ok I planned to conceive and I get what that means but I'm only just now 'getting' that means I'll be someone's mum and that someone will ALWAYS be there and I'm responsible for them!" I also had a "carol from friends" moment during labour where I was just plain knackered and had enough so just told the medical staff "nope not doing this today bye!" And actually started getting dressed and prepping to leave 
It's bloody hard work!
I have ocd which prior to dd was undx as I did a bloody good job at masking! Once I had dd it went seriously into overdrive, probably also fuelled by the mcs and a difficult (medically) pregnancy and birth plus dd was in scbu initially too.
I eventually disclosed to a hv and got some help, but not nearly enough and I now wish I had properly addressed it BEFORE becoming pregnant.
Finances - these need to be rock solid and as well set up for any eventuality as possible too. Being a sahm, even if married does make you more vulnerable and not just if the relationship breaks down. Which I have also experienced. But there's also the sad fact that unfortunately some men/husbands do become incapacitated/die young.
I've a friend who was a sahm to 2 girls with her husband self employed in a trade, he had an accident which meant he could no longer do the work AND he had no qualifications/experience to do work which wasn't manual labour. They had a very tough 10 years or so while he recovered, retrained, grieved the loss of the person he'd been and their change in circs and she felt forced back to work initially and he was a sahd for a while which he hated and it definitely had a negative impact on their marriage long term. They are still together (just) but it's been a really hard road and I've seen other relationships go through similar or even less difficult than they had it and it's not worked out for them.
You can't plan for everything but good life assurance and critical illness cover for you both is ideal. Also wills - including who you'd both like to have care of any children if you both were to pass - another situation I have known of happen where parents have died in a car accident, hadn't made a will and it was more complicated than necessary for the remaining family to agree who would have the dc and also how the estate would be managed regarding that.
Also discuss with your husband contingency planning for if you become incapacitated and unable to care for your child/ren.
Regarding whether husband will pull his weight - don't go on how he is on good days, what's he like when he's tired? Low level sick (cold, toothache etc) THAT is what will show you if he'll pull his weight when he's sleep deprived by an infant.
There's a lot to think about and consider so actually I think you're sensible to do so well ahead of ttc stage.