Sneaking Behind My Fiance's Back

I'm thinking about getting on birth control (maybe that chip thing they put in your arm) but I don't want to tell my fiance . I'm 27 (28 in Aug) he's 32. He wants nothing more in this world than to be a dad, (neither one of us have kids) and I know I don't want to spend the rest of my life with anyone else or have a baby by any one else. I'm just afraid to have a baby! I don't knw if i can handle the pressure, the responsibility, the body changes, the lack of sleep, money and free time lol. I dont feel like I'll be ready until im 30, but then he'll be almost 35 and feels like that super late for him. I don't want him to be expecting a baby that's not coming because I'm on birth control and he doesn't know...