Starting 30 day shred... Any advice?

Just quick back story: I am 22 years old. I dislocated my knee when I was 12 because my teachers forced me to participate in track and field. (I asked not to.) Since then, I've always had knee trouble. I hadn't exercised properly since I was 14 (the last mandatory gym class in high school).

I started 30DS with 2 lbs weights (water bottles). It was incredibly tough. I couldn't even do a single push up (I would just collapse on the down bit). I followed Anita almost exclusively. Lunges were really scary for me, because in the past, they had hurt my knee (not in the muscle-growing way, but in the painful-injury kind of way). Eventually, by level 2, I was using 5 lbs weights. (I actually had a cold for the entirety of level 2.) After level 2 (and the cold), level 3 was a joke.

Then I did Ripped in 30. Then Killer Buns and Thighs/6-Week 6-Pack. I do No More Trouble Zones when I want a longer workout. I'm up to 7 lbs weights for most exercises. (I use 10 lbs for renegade rows and deadlifts. I probably could lift more, but weights are expensive and I am poor).

Today, I just redid level 1 of 30DS because I have a cold (again) and I wanted something quick and easy. I'm using 7 lbs weights. I totally forgot that push ups were the first move, so when she's like "Let's do push ups!" I groan, get into position, and away I go. I easily hit 15 push ups (I couldn't follow their count because my head was down). I couldn't remember the pace, so I just keep going until she says we're done.

My advice is to JUST KEEP GOING. It doesn't matter if you don't hit the same amount of reps as them. It doesn't matter if you use lighter weights than them. It doesn't matter if you have to take a break in the middle--just keep going. If it takes you more than 10 days to feel comfortable at level 1, then take more than 10 days. If you can't do back lunges, do front lunges. If front lunges hurt, do side lunges. If side lunges hurt, go back to squats. If you can't do any lower body moves at all, just stick with the upper body (and maybe get a trainer from a gym who can find lower impact stuff for your legs). DON'T BE DISCOURAGED IF YOU HAVE TO FOLLOW ANITA. Follow Natalie when and where you can (because you'll see faster results), but do what you can.

Finally, for fellow knee-problems people: I use a yoga mat AND a very thick, folded up towel for any move that requires me to be on my knees. (E.g., modified push-up, donkey kicks, fire hydrants, etc.) I also use a knee brace on the previously dislocated knee. That usually takes away any discomfort I feel while doing those moves. Even though I have these knee problems, I listen to my body while still trying to push my limits. Can I do a jumping scissor lunge (from Killer Buns and Thighs, Level 2)? You bet I can. If you never try to get out of your comfort zone, you'll never get anywhere.

Most important thing to take away: After exercising regularly, I now have lovely muscles on my legs. This build up of muscles on my legs is EXACTLY what my physiotherapist wanted to see. (The muscles around the knee are much bigger, holding my kneecap in place.) I no longer have pain in my knee that wakes me up in the middle of the night. So those scary lunges? Not so scary anymore.