How important is dex for the fencing MA?

These past days i’ve been trying out Fencing and i have some questions, How importat is Dex for this martial art and if i should focus on other stats for more reliability. I know it makes you block more often but how much dex should i aim for? And if (for example) i have like 20 dex will i be unkillable? I have stats through skills and stats through kills so stat points won’t be an issue.