There was an article I read a few years ago when TTC but I can't find it which covered this and was v interesting.
To answer your question 1, yes. It seems to suggest that parental ages somewhat offset each other. Eggs are a bit more important than sperm in terms of the effect of age but sperm are still significant; a 38 year old woman trying to conceive with a 26 year old man will have an easier time than one trying to conceive with a 38 year old man, and one trying to conceive with a 48 year old man will find it harder again. (Obviously this is an average)
Re your question 2, there is a significantly increased risk of autism with an older father, and I believe other developmental delays.
I guess the question is, given your ages, if you are happy and able to welcome and care for a child who is more likely to have disabilities. If the answer is yes, then go ahead. An increased risk isn't a certainty.
But I would suggest you think about what you can do to offset the negative impact on your child. Are there other family members, cousins etc, who will support them and you if they lose their father young? Would they be financially impacted if he needed care while they were still in school? Your partner is the same age as my in laws who are active grandparents but tired after a day of full time care. My parents are mid-seventies so the same age he'll be with a primary/stroppy teenager and would in no way be able for more than a day at a time caring for a child, ageing has really started to become apparent in the last couple of years with them after many years of being healthy and active.
It's all chance but you stack the odds against yourself in your situation, however there are things you can do to mitigate.