When is it the right time to begin second series?

So my teacher James said I should start the intermediate series next week. I panicked a little as I can't even jump back properly (when I say properly, I guess i mean 'float' back) and still cannot jump through with straight legs (I can do crossed legs now).

I'd been held back for over a year with knee pain, knee clicking etc. but once it seemed to have got a lot better (they're not perfect and don't think they ever will be)  my practice has just taken off! Thinking about what I've achieved in such a short space of time seems amazing... padmasana, mari d, supta kurmasana, tittibhasana, bakasana with jump back and drop backs, all within 9 months. I can't come up to stand from back bend unassisted, (I managed it once but it has evaded me since :) but I'm dropping back at home most practices, the Lino Miele way (walking hands back down legs then letting go). So my question is am I ready for the second series?

I'm trying to think back to when I started the primary series... did I think I'd never be able to do them? Yeah, I guess I did, I certainly didn't think I'd ever jump through to sit, let alone get into supta kurmasana and dropping back into a back bend. I remember watching the teacher demonstrate jumping through and thinking, 'yeah right!!'. lol. It's funny how quickly things change. The time's gone by in a flash.

Kino MacGregor says that if you can hold UHP without any stumbling, bind in mari d, bind and get legs behind head (with help is fine) in supta k and drop back and come up in your backbends, then you may be ready for intermediate series.

So now I find myself here with the David Swenson practice manual open half way through and feel like a complete beginner. Again. But it's exciting. Very exciting. A new journey! New postures to work out, new pain and discomfort to experience!!! So today I finished purvottanasana then began the intermediate section. It all seemed to be going fine until laghu vajrasana.
 

OMG, it was hilarious, 3 options to choose from from David's book, and I still couldn't work out which one to do!! I think that'll be one to do with a teacher. It was like, 'if I bend here? No. If I do it like it this? No, that doesn't work. Maybe like this? No never going to happen!' LOL.

Kapotasana I managed to do option D I think, taking the hands back to the wall, but oh dear, I think my back has a LOT of work to do! I have a very flexible lower spine, but my upper/thoracic spine is so stiff it's unbelievable. The back bends left me thinking, will I EVER be able to do them?!

I guess I just have to look back and remember seeing tittibhasana or supta kurmasana for the first time!!

When I started ashtanga I really didn't know what I was letting myself in for. Before I'd even finished, sorry, even seen the whole primary series I was already booked up for David Swenson's retreat in Goa! It wasn't until I got there and was half way through the first morning's practice when I thought, wow this is long, I don't remember this posture...or this one for that matter! Complete shock. This time, I know exactly what I'm letting myself in for, I have books, DVDs and practice manuals and sheets to remind me! To remind me of how far I have to go, how long the journey's going to be and how much work I will have to put in every practice.

Luckily for me I can do the first 8 postures, I can even bind in Pasasana! And I'm looking forward to getting to grips with all the rest!