Background first, mechanics later.
You should, as I've said before, take these as only suggestions: if my ideas take your character in directions you don't like, then please, tell me so. I don't take offense at people rejecting ideas. Revise, take, or ignore as you like, but these are my flights of fancy for the day.
Let's put your social class as fairly well-to-do/minor noble status: you've lived on the City all your life, and your parents are two well-meaning wizards for the Blues (currently the ruling party). You were, as you suspected, expected to be a great and noble wizard, but you never just got the hang of all those weird sounding words, and instead, spent more of your time running around and getting into trouble (rogue 1). You then developed your powers in your early teens (rog 1/sor 1), but while your parents were happy to hire you a tutor to learn how to control your powers better, it didn't quite interest you as much as your interest in crafting jewelry.
While crafting got you so far, your parents just couldn't afford (and really didn't want) to support your habit, and so, you used some of your other talents, to break into people's houses and some stores, and steal precious jewelry. You've picked your targets carefully: picking people only from the Reds, people who seemed like bad eggs etc. You were actually making quite a bit of a name for yourself: there's a few stories about you in the Daily Float, actually.
I'm thinking that your hook in could work something like this (and might be interesting to play as a flashback sometime): on one of your jobs, you were just about to get the jewlery, when the lights switched on, and a small team of journalists were there, asking if you would care to give an interview. Before you could so much as consider, the City Guard showed up in force. The battle was not pretty at all, but you and one of the journalists (DE's character, if he wishes to go along with this, and maybe the budding romance idea), escaped out, mainly thanks to you and your skills not only with breaking and entering, but with the very quick leaving as well, and convinced you, and his editor, to sign you up on the Float. You've only done some very minor work so far with this new team, and are very much the new girl.
I see a lot of other directions that look interesting: maybe you own (or want to own) your own jewelry store, etc.
Some of the segues in there are loose: I'll leave you to fill it in, personalize it, if you like it.
Mechanics: (again, this is just someone who likes to wonk with rules occasionally)
So, first, impeccable choice of magic items: anybody who takes an immovable rod just makes my day. So, in case you've never seen master-of-arms, let me note that there is an immovable-rod weapon master prestige class (which you'd be able to take at 6th level, if you took 8 ranks of balance now and also quick draw as a feat), which contains all sorts of cool tricks (like being able to use it as a free action, using it and acrobatics to basically move in any direction you like, sticking it into someone's armor, where they can't reach the button, then activating it, using it to trip people, and all sorts of cool things). If you're interested, then let me know and I can send you the write up. The immovable rod, as a weapon, is d6, simple bludgeoning, 20/x2, medium size, and can be enchanted as any normal weapon can. (just add 2000 for the 1st plus, and so on).
Secondly, if you like this sort of revision of the concept, then rog4/sor1 probably makes a little more sense, you don't really get much with sor until 4th level, which is a while off, and you still get cool spells at 1st. If you're thinking of going into a prestige class soon like Immovable Rod Master, or Thief-Acrobat, then it's probably better to do rog3 (1st)/sor1/ftr1 (which could get you shot on the run now). If you decide to keep the dodge/mobility feat chain, since we're not going to be using battlemaps (and so those feats becomes less valuable), I'll give you the spycraft version of dodge: +2 AC to any one enemy, or +1 AC to all enemies. Or you might consider other feat chains, or just a random mix of stuff, like improved init, quick draw, weapon finesse (immovable rod), dodge or some of the stealthy feats from song and silence.
Spells: Ventriloquism is a good choice, but alarm is something that can easily be shunted off to a scroll or two, or a wand. Maybe, if you like this character revision, something like sleep, or feather fall, or spider climb (slippers of spider climb are also a good magic item to consider)? I'd also probably sub out ray of frost for daze, fits more with character, and more useful.
If you would like a ring of invisibility, but just can't pay the 20,000 gp, consider a x/per day ring of invisibility: 4,000 for 1/day, 8,000 for 2/day and so on.
Hmm. What do you think of all this? (remember, honesty first)