I agree with the age ranges provided by Sufia, but it must be noted that terms as exact as "early 40s" or "late 30s" are not commonly used as part of general conversations involving acquaintances that are not too familiar with each other, especially since a person's age is a bit of a delicate topic to discuss in most parts of the world. Maybe the aforementioned age ranges can be a source of discussion between close friends, but when it comes to determining a person's actual age, I'd take them with a grain of salt seeing as how people tend to not be completely honest about how old they really are (which of course is acceptable, seeing as how questions related to the same are very personal). As a result, it is often considered safer to use sentences like "The woman with the spectacles, is in her 40s" while referring to a woman of let's say, 47 years old, especially since being vague allows people being described on the basis of their age, to have more of an out. Of course, there are many people that also tend to be straightforward while discussing their age, but when you are in doubt, it is always better to just be formal at least initially, so as to come across as respectful of the boundaries of the person you are addressing.

So for 40-43 I will say early 40's? Thank you so much

Those markers are not used for exact ages, they are used to state the rough age/age ranges. Taking the 30s as an example. Mid 30s = 35, but you'd usually use mid 30s for someone who is 34-36 years old. 37-39 is late 30s. 30-33 is early 30s.

I’d suppose early is between 0-3, mid 4-6, & late 7>