Age is no doubt an issue but certainly shouldn't be treated as a form of bar. If you get cracking as soon as possible and maintain continuity throughout then I can't see why you shouldn't embark on the Type Rating soon afterwards. However the line training though extremely handy to have could potentially become a bottleneck where the TRTO supplying it need to negotiate such 'slots' with airlines and that's not a precise science. Nevertheless with the loco culture prevalent in the industry these days it's more to do with quality of hours rather than the bias towards quantity, but then again I'm no expert so I might be wrong. If nothing else at least you would have quenched your desires and not left 'wondering' in the latter years.