Hey!
You sound like you might be a great fit for our guild Impaired, we are a relatively new (7 months old) Alliance guild on Ravencrest EU. We achieved 7/10 Mythic Castle Nathria after coming into 9.0 late and are currently 10/10 Normal, 5/10 Heroic Sanctum of Domination. The goal this tier is Cutting Edge. We are a more mature guild with the average player age around 27-28 (we even have a Scottish raid leader so you’ll be right at home!) and most of us have played the game seriously since TBC/Wrath, a lot of us having even played together most of that time. We actively try to run Mythic+ with the majority of our current roster having achieved Keystone Master Season 1 and some on their way to getting KSM Season 2 already.
You can read more about our guild here; New 2 Day Raiding Guild - Alliance - Ravencrest. If any of this sounds interesting to you please get in touch with any member of the guild in game or message Brukerr on Discord Brukerr#1325 or Battle.net Brukerr#2705.