8 weeks is better than 7 weeks, but the most important thing is of course that the baby is weaned. Young bunnies are sensitive to stress etc, so they have a better chance of leading long healthy lives if they can be with their mother and siblings for their first 8 weeks.
If you have alfalfa-based pellets, you don’t need alfalfa hay. It’s actually good if you start her on grassy hay (timothy f ex) right away, because the necessary transition from alfalfa hay to timothy at around age 5 months can be tricky. Alfalfa is much yummier than grass hay but not appropriate for bunnies out of babyhood, since it’s very rich and has lots of calcium. Since you already have bought the alfalfa, I’d recommend you’d give her that as a treat, but let her have unlimited grass hay and pellets (unless she’s a perfect piggy, of course, then you need to ration the pellets.)
Oxbow pellets and their hays are what many of us here use. The most important thing with bunny food is that you NEVER give “bunny-muesli”. Also stay away from pet-store bunny treats like yoghurt drops, dried corn cobs and seed bars. Those things are really bad for buns.
Things to look out for in a baby mainly has to do with poop. Diarrhea is the main big danger for young buns and needs immediate emergency vet care if it happens. Hopefully it won’t of course, I’m only mentioning it because you asked.
We’ll be looking forward to seeing and hearing more of you and your bunny!