Hey Sticky,
Everybody's preference to trichome colour is different. Me, I like a 'weld my ass to the lounge' type stone, so I want my trichomes to be caramel/burnt toffee brown and I flower for a bit longer than most. But if you're after a more uplifting type stone, an earlier harvest can provide this. My only recommendation here is to wait until her white pistils turn brown at least once. Harvesting before they've gone brown once can make the smoke taste very young.
Now, for your question :- "Is this mould?"
I would suggest it is mould. Any damage, where the branch meets the stem can cause it to weep. The weeping provides the moisture the mould needs to flourish. As the mould spreads it damages even more of the stem, feeding itself from the moisture. Now, it looks like mould to me and the spores may have spread along the stem, but to me it looks like it's only a stem mould, not a bud mould. If it was bud mould, I'd say there'd be no question. Rip it. But stem mould can 'sometimes' be managed, if it's caught before those spores disperse.
Depending on how long you've got to go, you could carefully remove the affected stem. Any movement of that stem will disturb and release spores, so you've got to be CAREFUL. But here's what I did:
I got a plastic sandwich bag and slipped it over the branch, all the way to the main stem. Being careful not to disturb/move it too much. I then sealed the bag with tape and cut the branch level with the main stem, removing it from the growspace. I then place a smear clone gel over the wound on the main stem. The gel seals the wound and prevents it from weeping too much.
So, that's what I did.