Delayed ejculation?

Hi guys,
I have a question about delayed ejaculation. Right now I am on my day 51. Lost my virginity at day 35. I am having sex with my girlfriend ocasionaly. I dont have a problems to cum when having sex for the first time, but when we do it more that once a day, I can have problems reaching orgasm. Its not that big deal. My sexual health improved dramaticaly once I started having sex and thats great but I am still worried about this thing. I just dont know if its normal or not. We decided taht we will take a break from having sex for two weeks. So is it normal or not?

Thanks