Maybe I can help you out a little bit as well.
So I'm 20 now, but I was 19 when I get the car 7 months ago. My parents paid for half of it but I wasn't forced into buying a specific transmission. I got to pick the manual like I wanted, and the main reason I wasn't forced to buy an automatic is because no one else is going to drive my car anyway.
Is your mom making you pick automatic because she wants to drive it, or is it another reason? If it's not because she wants to drive it, try to convince her to let you get the manual, especially since it's cheaper to buy, and cheaper to maintain in the long run.
I'm not saying the automatic sucks or anything, but you said you want the manual. The problem isn't with the automatic, but the problem is that if you get the automatic, once the honeymoon phase is over, you're going to wish you had the manual like you originally wanted. It'll be one of those "what if" type situations. You'll learn to love your car but there will always be something nagging you in the back of your mind, thinking MAYBE you should have gotten the manual.
You could talk to your mom about why you want a manual, and try to convince her. Maybe even offer to teach her how to drive a manual if that's the reason she wants you to get an automatic.
Either way, hope you get your car soon, and hope you enjoy it!
Edit: I forgot to mention that I do daily drive my FR-S. I drive about 40 miles every day, going to university, and work, and sometimes even more than that if I have plans to go somewhere on the weekends and stuff. My schedule is mostly quite nice and I manage to avoid both the morning and evening rush hours so I'm never really in stop-and-go traffic anymore, so driving a manual is quite fun with open roads. When I am stuck in traffic, it does get a little tiresome to continue riding the clutch to make the car move an inch at a time, but you get used to it after a while.