i go on dantooine first
You shouldn't, if you start with Nar Shaddaa you get more party members right off the bat thereby you get more time to gain influence with them...it makes it much easier getting full influence with them all
I want to get a lightsaber first
You can still get one on Nar Shaddaa
Gotos Yachts Defencesw Are to poweful at such a low level jacks
Try taking (dark side) Hanharr with Rage equipped and Atton (light side) Atton and Brianna with decent armor or Visas or Kreia.
It's tough in some areas but can be done, if you have to strategize before moving into each room and area (be sure to have a decent melee weapon) with shields equipped, try picking off the turrets from a distance with Atton. If need be take lots of advanced medpacs with you...
The benefits of doing Nar Shaddaa first I feel pay off towards the end of the game when things unravel.