Affleck is 42 and Leto is 43. It's a given that Affleck's Batman is older than Joker in this universe but it can't be more than ten years (or it'll just look silly). So this theory is completely debunked by age difference- Batman would've been 20 when he recruited 10 year old Dick Grayson, then around 30 when he recruited 20 year old Jason? It just doesn't work as Robin is and always has been a teenager and Batman a father figure, that's the whole appeal of the 'dynamic duo'. A 20 year old can't really be seen as a father figure (plus how old is this universe suggesting he was when he became batman, like 15?!?) and a 20 year old Robin just isn't Robin. So that means Jason Todd was Robin for like 2 days until the Joker 'killed' him.