So, the structure will probably be easier to have confidence about if it weren't so complex - and so protracted. You will better impress with your English ability if you're using more advanced techniques appropriately. Below, I have re-written this sentence as more than one. I have explained it as I go along, breaking it into chunks with commentary. I do not want you to just use this; I want you to understand it, and tweak it so it's more what you want to say. I've not made any major changes to structure or meaning.
Over the past 6 years, I have grown tremendously from a newbie who could barely write 10 lines of code without errors to a seasoned programmer who can manage a software project that consists of thousands of lines of code.
That's a reasonable sentence there. It's longer than necessary, but if part of your intent is to demonstrate English this goes a long way towards that by showing a sentence with several verbs properly interconnected, not all in the same tense (a not uncommon novice mistake, thinking they should be), subordination done nicely. It reads like a sentence from a native speaker, albeit one who has a penchant for expressive language (which is not always a bad thing). Depending on how formal you want this to be, you might want to consider replacing newbie with novice, which is much more suitable for a formal register.
I have developed from being lost whenever a program crashes for seemingly no reasons to being confident - and patient - every time I set breakpoints and single-step through a faulty method or function.
Here you get to build up a little anaphora, a technique that a novice might stumble into but you can show you are using deliberately by changing a word for an appropriate synonym or near-synonym. Similarly, removing repetition by replacing one every time with whenever makes something that reads more fluidly, and shows that you can find alternative ways to say things. The setting out and patient as an overt parenthetical (you could use commas for this, the choice is stylistic - parentheses are less appropriate for that sort of parenthetical in this sort of context) is a matter of style, and you can take or leave it, but it shows the use of another device.
(By the way, and this is programming-specific, I'm not sure you really need to say "method or function"; the people reading it aren't going to assume you don't know that you use different terms in different languages/paradigms.)
Now, for the last bit, you've demonstrated a parallel structure - let's show that you can say the same thing with a different structure.
from not knowing where in the intimidating lines of code is mistakenly altered to utilizing version control systems like SVN or Git to ease the whole development process.
When I started out, I would have no idea where in a file filled with intimidating code an error had been introduced**; now** I make sure to use version control systems like SVN or Git to help track changes, and ease the whole development process.
In this new structure, we are contrasting the state at different points in time not by indicating movement, changing from one to another, but just stating the different states. We use a prepositional phrase to introduce the old state, locating it in time, and the very simple now to introduce the second. The two are separated with a semicolon because they are free-standing sentences in their own right, but you wish to indicate that they are more closely associated than they would appear with a full-stop. I also added an explicit indication that you know why version control would help with that situation, just in passing.
Convoluted sentences prove you can keep track of a long sentence, but they are hard to read and not usually useful. Demonstrating the same sort of thing across multiple sentences, doing it in different ways, is easier to read, more effective communication, and more impressive.