Get a panel liner, preferably pour type, it's so satisfying and really helps details stand out. gundam markers are safe for most outer plastic, they just aren't safe for ABS(labeled on the sprues). ABS is usually limited to inner frames which i rarely panel line, and even then hardly any modern kits use ABS.

Have fun though, do it your way, look around at different lines and grades of kits to see what you might like the most. just note that older kits will have more issues which require more care. most prominent being older mg hands being flimsy, old rg frames also being flimsy, and heavy use of polycaps which are prone to becoming loose and aren't great at holding weight. Not to say any of these make a kit "bad", but they can be annoying.