Nice!
I use a condom with any girl I don't want to have a baby with. Even if they are on birth control. I just don't trust girls with that shit.
Condoms are 100% effective if you use them right. Any statistic less than that is for people who are foolish with them.
Check the thing periodically, if you drip pre-cum into it it can get moist and slip off. Change it when this happens - through a long session you can get through 2 or 3 condoms.
Check it just before you cum.
Then check it when you have filled it with man juice. As you remove it squeeze it to check for leaks, even fill it with water under the tap if you are unsure.
Reframe any negative beliefs you have about condoms, they are great.