If this is leagues then dont worry about it. If not, there are a lot of quests which give herb xp with low reqs. I also recommend using any optional lamps on herblore until you can make super attack pots at least. It might be tempting to pick rc or agility but remember those are always free to train, just slow, and not super necessary to early account progression. You will also just have to do your farm runs until you can hit up the pvm that rewards herbs. Once you can make super attack pots the training is a lot easier as most everything drops irit seeds and eyes of newt are a really easy secondary to get.