-- It was determined that Rictor was 6 years old when his father died.
-- When he was 13 he was rescued from the Right by X-Factor (and was revealed as the youngest member of the X-Terminators besides Leech and Artie).
-- In X-Force #12, Rictor reveals that it had been 10 years since his dad died. Using this (and the fact that it was stated months had gone by since he left the New Mutants), we can say that he spent approximately 1.5 - 2 years with X-Factor and the New Mutants...probably leaving the New Mutants when he was 15.
-- Sam turned 20 years old within the first few months of X-Force. He was revealed as the oldest member, Siryn was deaged and confirmed to be the second oldest member a few years later, which would mean the "kid" known as Shatterstar could not have been any older than 18 upon his debut. 18 would have to be the max since Terry wasn't close to being 20 and Sam "just" turned it. Shatty could have been 16 or 17 (Feral and Tabitha both would have been 17 -- Tabby because she is a year older than Ric, and Feral because it was stated in canon). Shatterstar was probably 17 or 18 just based on his teammate's ages...so right around Ric's age.
--Rictor joined X-Force just before the X-Cutioner's Song, which took place over the span of a few weeks based on the information regarding Xavier's condition and how long it took X-Factor and the X-Men to track down X-Force. It was stated that exactly 3 weeks had went by between X-Force getting arrested and issue 19. So between Ric joining in 14 and 19, it would be safe to say that quite a few months went by.
-- Cable came back from the dead in issue 25, where the boys confirmed that it had been several months since they last seen him (Sam seen him last in X-Force #18). This would mean that probably one year went by between the time Rictor joined and issue #25.
--Reignfire happened in issues 27-28, and when Sam left to go home on vacation in #29, it had been confirmed several weeks had gone by. 29-30 took place all in one day, as well as 31 happened around two or three weeks later. 33 was the crossover and had gone on over a span of many days. 34 picked up right where 33 left off, and Rictor has gone back to Mexico for a couple of days based on flight times. So it's probably safe to say that about 6 months had gone by from #27-34
-- It had been confirmed (XF #68) that exactly 3.5 years went by between issue #35 and issue #68. Within those 3.5 years, Rictor left for Mexico for just "a couple" of months (so probably 2-4 months). So EXCLUDING Ric's trip to Mexico, the boys were in X-Force together for four/five years. Which would put Rictor at the age of 20 when they left (which makes A LOT of sense because the 'roadtripping' X-Forcers were confirmed to be "Twenty Somethings" and he was the youngest of the group)
-- "Many" months had gone on between X-Force 70 and 76 (based on Domino's monologue of not seeing them in that amount of time)
-- A "many more" months went by between X-Force 76 and the '99 Annual (once again based on narration boxes)
-- Only a few weeks went by between Rictor joining X-Corp and X-Factor (based on Rahne's comments about Jamie being on the team in Madrox #1)
-- Wolverine stated Shatterstar had been off the X-radar for "months" in X-Force Vol 2 #4.
-- 4-5 months went by between the Shatterstar LS and XF vol 2. In Shatty's LS he had been doing his 'job' for just a couple of months.
-- Rictor was confirmed a member of X-Force in Cable and Deadpool #18. Which took place an unspecified amount of months between X-Force Vol 2 #6 and C&D #18. C&D #18 took place approximately ONE DAY after M-Day...which would mean Rictor was depowered while with X-Force (presumably).
-- X-Factor #1 took place just a couple of weeks after M-Day.
This would mean that they were probably in Mexico together for around a year or so. So they would have been good friends for close to six years by this point.
ASSUMING Shatty took off to Madripoor immediately after leaving Mexico, it was probably about half a year before he would have met up with Rictor again around C&D. Which would mean that X-Corp would have taken place while Shatterstar was in the Sarcarium with the monks in Asia. Rictor probably left X-Corp around the same time as Jamie quit then, to give him a few weeks (months, maybe, if he left earlier) with X-Force. (It was also confirmed X-Corp Paris closed its doors after the bombings.)
-- Between issue 1 of X-Factor (Vol 3) #1 and the Civil War tie-in (#8 and 9) a few 'weeks' had passed since Rictor joined up. It would be safe to say that Shatterstar and Domino destroyed the X-Mansion the following week (after #8-9). Publication dates confirm that "X-Force" (Star and Dom) blew up the mansion AFTER the X-Men confronted X-Factor about hiding Pietro in mutant town.
--And since Siryn has only been pregnant for 5 weeks....Rictor has only been in X-Factor for 2-3 months now. :)
And since Rictor was 20 when he left X-Force in #70, he would've been around 21 when he joined X-Corp. And since just a couple of months have gone by since he joined X-Corp, it would put him close to 22 now...meaning Shatty wouldn't be any older than 22-24.