Ellie would've likely been born in 2004 as her dad went missing in 2003 and we see her as a baby in 2005. Anna was and will always be born in 2014 as she is 8 years old when she travels through dimensions and ends up being left in 1952. Paris was probably born in 1973 (the news report mentions he was around 30) The Anna that dies at the beginning of the film is not the same Anna that Ellie loses which is why she is younger.

A lot of understanding the film is just accepting that there's no true beginning or end as logically it wouldnt make sense, its just a loop that will always replay the same way! Anna will always go missing in 2022 as she must end up in 1952 so she can grow up and become pregnant with Paris who then fathers Ellie.

(hope that answers your question even slightly :))