Trouble giving best friend this present.?

OK, there is this girl who is my absolute closest, most dearest friend. I also am in love with her too. She's just perfect in every way possible and we're so close. She knows what I want to do with my life and really admires it, her dad was in the military too. But anyways I am giving her a present tomorrow for her birthday and im kinda having trouble explaining it. It's my U.S Army watch I got for Christmas this year, and I plan to apply for West Point and be commissioned in the Army. I want her to hold on to it until I leave or return. I'm not sure. I know this must sound really weird, but I see it as a symbolic thing. I feel like I want it in her possession before I take it with me for those long 12 years I plan to enlist with the military. I need help trying to come up with what to tell her. I know only i can really tell her what im feeling, but maybe someone will have an idea for how im feeling. like me and her think alike and can understand each others situations.