Please help! Newbie screwed up??

Hey guys this is just a pic from one of my plants in my small backyard guerilla grow, one of the problems that has come to my attention is the apparent yellowing of the bottom two leaves, the cotyledons which have died along time ago did the same thing so I was curious as to whether this is normal? Im also aware that this cpuld be a nitrogen deficency and by growing autoflowers ive already switched to blooming nutes which contain little to no nitrogen, any help to a newbie would be appreciated

be careful using blooming nutes early in the grow. they do not contain enough nitrogen to keep the plant green.
this is a pic of one of my C99 plants that are fed nothing but Jack's 20-20-20 and occasionally CalMag.

It is normal for those single point leaves to die early.