DMF profession quests are giving knowledge and mettle, both of which are hard to come by, so do the DMF quests this week while you can to get a little boost to your professions, all professions, not just the crafting ones.
If you’re still leveling your professions (especially crafting ones), I’d wait until you hit a cliff. The free points from the DMF quests are great for getting past those annoying points where you only have green (or very expensive) recipes but are a few points too low to pick up new ones.
There’s zero reason to rush and do them. Wait until you stall out because most professions you’re going to get to 65-75 and it’s not going to be realistic to get the skill points without crafting orders which people don’t even do.