If your just about to begin save as soon as you leave the doc's and defiantly before leaving goodsprings for the first time ad you can change your stats of your not happy with them

As a first time player you may not be familiar with DT and the combat style in NV, and are using guns.
My advice take a shotgun, single or caravan ( caravan's best ), head to a work bench breakdown some 20 guage and 12 guage shells, plus all the 22's and some 38's.
Then make as many slug shells as possible for your shotgun, and raise your gun skill asap and take shotgun surgeon as a perk.
This will make facing any armoured or unarmoured foe apart from a deathclaw an even challange, even if it's way beyond in difficulty when you should be facing it.
As sometimes the game pops up some dangerous spawns in early areas, and having something to take them on will save losing half an hours gaming or more if you forget to save, and are caught by some hit squad.

Repair as a skill will help with this as well.