Hi Kenneth, I'll weigh in on the side of buying a used bike that you can afford now, or even in another month and you'll still have several months of riding. The season isn't really over, especially in your part of the country, until Oct or Nov, maybe later depending on the weather.

If you can do it without borrowing, or maybe, as someone suggested see if your boss will let you pay off the bike from your wages, you'll be independant of any debts. I would be very careful about borrowing from friends, money can easily come between people.

Maybe you can come up with alternate arrangements for storing the bike, getting rid of one of your Mom's arguments.

Your Mom is just trying her best to protect you, it's up to you to show her you can be responsible.

Good luck!