Is this what is nimitta is? From my understanding, The nimitta are signs you should be looking for during your jhana meditation. Like once your focusing on your visual object you will notice a white light. Thats a sign your entering acess concentration. Or you may notice your breathing becoming very faint. Thats another sign.

Is this correct? Is there certain signs i should look for during my jhana meditation?
It is not correct.

As Suminda Sirinath S. Dharmasena says in this post (Does contemplation activity, before hand, give rise to the mental image?) in this context, nimitta (that we usually translate as sign) refers to a mental image. In case of concentrating on the breath, it says it resembles white light.

But the measure of achieving an access level is not just that, for the mental image of the breath is found way before, according to Abhidharma. Before the access level, there is samatha, and the measure of achieving samatha are physical and mental pliancy, and physical and mental bliss. As long as these pliancy and bliss are not present, you can be sure you have not obtained samatha, much less the access level. That pliancy is the direct antidote to laziness, which means that one can at last meditate for as long as he wishes without experiencing discomfort (no more backache, no more unwilling mind that you feel you can not bend, etc).

You should not actively seek for these (pliancy, bliss, and even the finding of the mental image of  the breath) because it will make your mind tight and narrow. We do not meditate just to cultivate more attachment. Rather, you should count on ethical discipline, contentment, few desire, the lack of many discursive thoughts, regular and repetitive practice, and an understanding of the Dharma to lead you there eventually.