Truth be told at your stage of your career, I don't think anyone will hold it too much against you as the only thing most employers would have lost is the cost of recruitment and opportunity to hire someone else had they been able to offer that one more position (this will vary depending on each company/firm though). That being said, having a bit of humility in knowing how you have mucked around the company you did sign with and the implications, would help improve the likelihood they will you wish you well. Your reasons don't sound unreasonable particularly if it's not near to you but that being said, these are all factors you could have and should have considered prior to signing - you don't discuss the terms of an agreement after you have already signed and committed to it!
Either way, if you do get an offer for Company Y and that's what you really want, there's no point doing something you really don't have your heart in. It's like people who drop out of accounting cadetships when they find out they got into medicine. It happens, people get it, etc... but it still annoys people.