Topping must be done when the plant has 3–4 nodes, but since autoflowers begin flowering by the third or fourth week, the plant should display 4 nodes by the beginning of week 3. So I would say you did it just in time and everything should grow as normal. I will say that I've learned that when topping autoflowers sometimes the buds don't get as dense compared to a non- topped plant. Hopefully, I answered your question and remember Happy Growing and Free your mind one puff at a time.