feeling guilty ttc ?

I'm ttc my 2nd baby an so is a very close friend. she's been trying for over a year an it hasn't happened yet I've held off ttc because I will feel so guilty if I find out I am pregnant before her... I really want to enjoy this pregnancy because my 1st wasn't a great experience I was so sick.. I don't want to hold off too much longer as my son is 2 and was hopping that I would have 2 children close in age so they could be close growing up. I don't know what to do ? anyone any suggestions? ?