I had antibiotics for a womb infection and got thrush at 3 weeks, now 12 weeks and still got it, baby no longer feeds from me because she wouldn't once the thrush was established so I exlcusivley express feed. I'm very susceptible to thrush so hopefully this won't happen to you but the quicker you notice it the better to get rid of it - mine got so bad because no one noticed. So warning signs are: very pink shiny nipples, or can be whitish, deep shooting pains in boobs, baby getting fussy at breast and pulling off crying, and of course eventually terrible terrible itching which makes you want to scratch them with a wire brush!
I'm sure you'll be fine though and ways to try to prevent it in the first place - wash boobs after feed to get rid of milk and dry thoroughly. Only wear cotton bras and change breast pads regularly. Thrush likes warm, moist, sugary conditions which is exactly what breast milk creates so the drier you keep everything the better. Hope everything goes well for you xx