First of all you need to ask yourself what is your priority now. Career or family? when i gave birth to my son last year, i told myself that my family would be my first priority cos i want to be with my child throughout his growing stage. I forgo my promotion last year. No regrets, cos i am with my child in every of his growing milestone. it is more satisfying than having a promotion at work.
You did not mention what industry is the company in there unable to advise on the long peak period.
but think about it if you were to OT till 8pm everyday, by the time you reach home most likely your child would have already sleep. There is very little time for bonding with the child.
Now i leave on the dot to make sure that i reach home early so that is still have some time to play with my son before he goes to sleep. but sometime still feel very tired no energy to play with him.
Give it a careful thought before you make your decision. My personal view, i will not take up the job. Maybe for the time being look for part time job first.