Not well endowed? No problem,

First thing is this, the space from the opening of the vagina to the servix is approximatly 5-6 inches, so even if you really small and a 4 you still have the ability to satisfy her

Second thing the pleasure women get is mainly from width not length so either way you should be okay.

Confidence is you main problem here if your not confident it can cause several other problems, think positive thinl things like
Every porn i see the guys penis' arent average the over average mines fine
I can still satisfy her anyway.
Atleast its not smaller
Atleast i have the oppurtuny to get laid
Atleast im bless with my talents
Atleast my penis actually can get hard. ( this problem is way worse trust me)

More things to help out-
Women can get 2 kinds of orgams vaginal and clitoral, clitoral is the better orgasm they get and you dont need a penis to do that.

Multitask in bed, ive given a girl an orgasm from a back massage, rub you body on her whisper in her ear pull her hair, you have 7 or 8 limbs/sex appeal that you can use at the same time, ive been practicing independing movement of each limb, i can use up to 5 at a time and im still working on more

while having sex always make sure your stimulating the clit as well it works better..

make sure you have alot of fourplay before hand

make sure you hit atleast 5 of the points on a womens body to turn them on.

when giving oral use your thumb to push up on there upper pubic region, it gives more sensation to the clit, also be gentle

try to finger her at the same time of oral. be sure to put your fingers on the top wall of the vagina, most of the sensation is there, there are ridges up there if you find them rub them that feels the best.

Pick you sexual positions carefully, you dont need to be endowed to satisfy a girl, the main advantage of it being bigger is you can do it from different angles easier.

The only thing having a small cock means is that you may not do some positions as easily, or at all.

Most women have more need for clitoral stimulation than vaginal. Since most women are more used to clitoral orgasms than vaginal. (clitoral is usually the first one they discover, and the easiest one for them to give themselves)
So rubbing her pussy is more likely to give her an orgasm than poking her with a big dick.

And anyway, a woman's orgasm is about 80% cerebral. (It's in her head.)
You can give a woman an orgasm through your voice alone... trust me, you can.
You can literally persuade her body to come using no physical stimuli whatsoever.

Aren't women fascinating ?

So if a woman can come, (and given enough time and effort to anchoring this, this is plausible) by you looking at her in a certain way and saying "come like a good girl", how much do you think it matters whether you have 5 inches of flesh or 9 ?