Look, I'm not going to disagree with you that an autistic baby isn't a perfect baby. To me, all babies are perfect in their own little way.
It is rather disingenuous though to say it's fine if someone has an autistic child because there's a statistically slim chance that they'll be unaffected by the societal barriers around them to the degree that they'll make entrepreneurial or financial contributions to society, or display their value in a way that will benefit society at large.
The OP is just worried that the statistics are less in her favour, and what she needs reassurance of is that she will probably be fine.
Autism is such a huge spectrum, and it is by it's very definition a disability.
My little boy is absolutely perfect to me, and to my family, but I wish I didn't have to go through a 4 year battle from nursery to year 2 to get him an EHCP and an even longer battle to get him into a specialist school. I wish I wasn't still changing nappies when he is nearly 7 years old. I wish he could write his name without someone also holding the pen and guiding the letter formations. I wish, I wish, I wish. I knew when I chose to have a baby that there'd be a chance that they could be born with a disability, or that at some point through their life they could encounter a disablng event, and I knew I would love that baby ever so dearly, like I do. I love him so much, enough to fight for him and his needs despite the isolation and loneliness, and the ever increasing public view that he's a drain on societies resources. I wish I didn't have to go through the heartache of wondering if my child will ever say my name, or be able to tell me when their tummy hurts, or if someone is bullying them, or if someone has behaved inappropriately towards them or taken advantage of them.
I didn't get diagnosed until right before my 29th birthday. I wouldn't want a child to have to go through school doing silly things, and getting into trouble for it, and not realising that the only reason they were doing those things was to fit in because for me, it was so desperately lonely, other children could tell I was just different and avoided me. I wouldn't want my child to grow up and struggle in the workplace and not know why they were struggling or be challenged at every step when they asked for accomodations to do their job to the same capacity that everybody else could. I wouldn't want my child to have the significantly impacted mental health that comes with it all. I wouldn't want my child to feel like if they were unable to work, they were worthless, didn't deserve nice things, and should just exist in pure survival all of the time.
This is what it is like to live with autism. We don't all get the savant type, excellent pattern recognition that enables us to succeed and become multimillionairre tech bros. Many of us don't even make it to IT college, or any college.
I think the OP is being sensible in understanding that the figures for these conditions do increase with age, but it is also right to point out that the biggest factor is genetic, and if neither she nor her partner are autistic, then the chances are significantly reduced. Many, like me for example, don't find out until after their child is diagnosed though.