I got an interview yesterday, and then 2 hours later, they emailed me with the offer in my email. In the interview, they asked when I was looking at starting, I said " probably at least a few weeks after my graduation date" (May 8) because I am taking the Engineer in Training exam after and then wanted a mental break after that. No date was said and they seemed fine with it nor pushed for any specific date.
In my contract, it says May 26 as the starting date, so it seems the employer took "a few weeks after" literally, which is fine, and makes total sense. But since no date was said, is it reasonable to start later (3-5 weeks instead of 2)? I do have a one week trip in there which is one of the main factors, but if I'm potentially gonna be working here for a long time, I'd think a 3 week extension wouldn't be too big of an issue.
How can I ask for different start date after receiving (but not yet signing) offer?