Hi,

You did a fabulous job breastfeeding Anna so well for so long.
It can't hurt to take Lecithen supplements from the start.
However, it's unlikely that you are "prone' to mastitis, and I wouldn't expect it to be an ongoing issue. It was more likely linked to early breastfeeding management. Most women have relatively too much milk in the early days. And often complications of birth (sleepiness, jaundice) mean babies may not feed well, leaving mum's nipples cracked and damaged and open to infection.
Whenever your breasts feel uncomfortably full, feed your baby or express some milk until they are comfortable. This will prevent painful engorgement and make it easier for your baby to latch on.
If you haven't done an ABA breastfeeding class yet - it may be well worth your while. The more you understand about breastfeeding the better it goes.
From personal experience, I suffered repeatd mastitis with my first child. (In hindsight, I went back to work very early and my breasts were often painfully engorged) With my other children I rarely suffered it at all