Tengo que felicitar a nuestro amigo "A donde Fueres.." por su tan acertada exposición en cuanto a los hechos que se mencionan. Asimismo, creo que aunque yo misma intentase reproducir el contenido de su discurso, me sería de todo punto imposible llevarlo a cabo con tanta precisión, acierto y exactitud. Además quiero añadir y añadiré, que a veces, no solo se precisa dominar la forma hablada como la escrita, sino que en esta última es conveniente dar correcta forma a su redacción. Procurando no hacer caer a los lectores en un aburrimiento y hastío profundo, comunicando de forma constante y reiterada los mismos mensajes. Por lo que suscribo lo dicho por "Adonde fueres" en todos y cada uno de sus puntos y además reseño que el camino del aprendizaje debe empezar siempre con una buena dosis de humildad.

Paz y amor!

I think that you should:

1. Do what you want. (obviously) :)

2. Go from one language to another when you feel you have reached your goals in the first language or task.

3. Why learn Russian? Do you have family that is Russian? Good friends that are Russian? Why not German, French, Latvian, or Chinese? I think that examining your motivations for learning language X will help you see if it would be a long-term, sustainable goal or something that you wouldn't be able to keep doing month after month.

4. Please temper your enthusiasm if you can, something like "writing as a native" is a very...optimistic way of rating one's ability unless the person in question has lived many, many years abroad. Like 10-20 years abroad fully immersed. I myself thought like you when I was literally one of the best Spanish students at a very advanced semi-immersion program at one of the elite colleges in the US.

And then when taking university classes with native speakers at the University of ____ in Spain I realized how much I didn't know. It happens to all of us and I hope it isn't that big of a shock when you go abroad and realize that there is so much to know in a language. In fact, every day I realize I don't know jack compared to what a native Spanish speaker knows or that I myself know in English. Not just vocab but, especially, the connotations of words. Getting the "matices" right is pretty hard and takes many thousands of hours to get down pat.

With that said, I wish you good luck in your endeavor. :)

In one word, yes!!

It's interesting because I've been pondering the same exact thing.

It sounds like you are nearly biligual, which should make it much easier for you to learn another language. 

Supposedly the younger you are, the easier it is to learn a language. Therefore, the time is now (or at least very soon); don't put it off to another x many years.

Don't ask why...ask why not.

I think you have to ask you yourself ´what is my object of my Spanish language? or what things I want to enjoy before study other languages.

About write like a native, maybe you write without error, but write like a native is not write without error, you have to make text that are easier to read for Spanish speakers, that Spain07 tell you. 

What you're saying is... it's impossible to speak as a native and write as a native without living abroad? I disagree.