The phrase "achieving their first" is correct and usable in written English.
It can be used when discussing someone reaching a significant milestone or accomplishment for the first time.
Example: "After months of hard work, the team is finally achieving their first major project milestone."
Alternatives: "reaching their initial" or "attaining their first".
The latter two countries are embroiled in their own space race on the Korean peninsula, with North and South achieving their first successful satellite launches this year.
And with Sydney and Melbourne achieving their first goal of a debut appearance in the knockout stage for the first time, there is no reason not to dream.
When Millie and Billy were achieving their first success, Mr. Leen explains that "the days of sleeping in the trailer were long past".
From an industry viewpoint, it was a risky move, coming so soon after achieving their first number one with 2013's Opposites, even if that sprawling double album was perceived by some as being pretty iffy.
During that economic turmoil, Mexico's opposition forces were achieving their first major victories in local elections in the north, and in 1988 dozens of entrepreneurs ran for Congress representing the National Action Party, including Mr. Fox.
It might explain why, soon after achieving their first US No 1 album, with 2011's The King Is Dead – the result of a decade of graft – they opted to take a career break.
G.M. and Fiat say they have reduced costs by teaming up on purchasing, but the two companies are still a year or two away from achieving their second goal, joint production of engines, transmissions and other elements of a car's power train.
The Crusaders bounced back dramatically in 2002 when they went through the Super 12 season unbeaten, achieving their fourth title.
Achieving their third No. 1 in the UK albums chart, the disc also featured the No. 2 single "Be Quick or Be Dead" and the No. 21 single "From Here to Eternity".
All my friends had achieved their first choice and I just felt really disappointed in myself.
Both had achieved their first big success with the backing of an established older man.
