Need some advice!!

Hey guys!! I'm 17 years old gonna be 18 in 2 months but anyways I been with my boyfriend who is 19 for 9 months and let me tell you I am madly in love with him I know I'm young and what not but I'm not stupid this man is my soul mate. I wanna give him a piece of my heart but I am very scared of pregnancy it's the only thing that's holding me back... I'm definitely gonna use protection a condom spermicide and Ella just in case. I'm gonna be having sex 6 days after my fertile window. Any tips? Do you think I will get pregnant? Should I buy an ovulation kit if so which one?