There are many things we just do not know about Saul/Paul....
For example some Jewish boys start their training around the age of 13
(this is usually phrased as "becomes obligated to fulfill all of G‑d's commandments.")
However, some Jewish traditions vary ... "The Code of Jewish Law (O.C. 581:1) instructs congregations to seek certain qualities when choosing a cantor to lead the services on the High Holidays. One of these qualities is that he should be at least 30 years old. "
So it seems some have an age restriction before being placed in a leadership position.....
We do not even know the time line for Stephen -- for example we are told in Acts 6 (5-6) that Stephen was one of the seven chosen as a deacon -- to oversee the distribution of food.
Based on the very short description -- we have the apostles having such a large number of conversions -- they needed help --- I suspect (but cannot prove) that we are talking at least a year here.
Then you have a timeline of Stephen performing his duties including many miracles and debates. -- this is possibly another year.....
I read some material that suggest Saul became Paul in 34 to 36 time-frame -- which if the crucifixion happened in 30AD -- would make it 4 years already in the Past.
So the stoning of Stephen was approximately 2 year (possibly more) after the crucifixion... (remember Acts covers at least a decade or more) -- the Jewish council happened in 49/50AD and (Acts 15).....
Also, remember THE BOOK of ACTS --- did not record "day to day" activities -- but Highlights that Luke thought was important to record in his second book.
The point I am trying to make, is that based on the Acts story line -- we do not know the age of Saul/Paul at the stoning -- there is some suggestion that Saul -- arrested and jailed "followers of the way" for quite awhile before he had enough leverage to petition that he get to go the Damascus....
So anywhere from a few years to possibly 10 years.
We do know for sure that after Damascus -- he went to Arabia desert for three years -- BEFORE even speaking to Peter and James in Jerusalem
(though that entire episode in ACTS is only a few sentences in length.)
So as near as I can tell -- Saul/Paul was either a slightly over 13 at the stoning -- since he is identified as a young man (and Jewish Boys become Men at 13)
which makes it plausible Saul was not even in Jerusalem -- before the age of 13. Which could mean he never had a chance to meet Jesus face to face (or even from afar)
There are a few story-lines that say Paul the Apostle was born AD 5 Tarsus, Cilicia, Roman Empire --- his missionary journeys occurred in late 30's though the early 50's -- with his death somewhere in the 60's.
I really do not know, but I suspect Saul/Paul never really "saw" Jesus either during his lifetime .... only after the vision......