Hi, i'm interested in bitcoin, i started in 2012-2013 but then i stop and lose every bitcoin.

Now i want to start again, i have some question if someone can help me:

1) Is a good moment for start to mine?
2) I have a good pc with 2x GTX Asus 1070 and a GTX 750ti, can i mine good or not?
3) I need to start from some altcoin and trade for bitcoin?

(sorry for my bad english)

I hope someone can help me! Thanks!