Others may differ, but I'd suggest you hang fire for a while, lest your enthusiasm gets the better of your judgement.
If you're confident that agents/publishers will be so impressed with your exquisite prose and highly marketable brilliant-story-well-told that they'll forgive its being incomplete, and be happy to wait breathlessly for its conclusion, you've nothing to lose by shortening the lengthy process of getting it onto the bookstands.
But if, on the other hand, you suspect it might not quite be the novel that redefines fiction as we know it, there are good arguments for finishing it first.
1) You owe it to yourself to give yourself the best chance of success, and until you've finished it you might not know how to begin it. It's a common experience among writers to find that when they've finished a book they need to re-write or at least re-shape the early chapters, to properly set up the story/plot and the characters.
2) It's never a good idea to show anyone that 'counts' an unfinished WIP. Anything less than perfection, in your own terms, does not show your talent to its best advantage, and as a beginner you're more likely to be judged on your text's actuality than your 'promise' as a writer. There's talent and promise aplenty in this highly-competitive marketplace, but relatively few publishable/sellable manuscripts. Publishing houses and agents have much scarcer resources these days for editing promising scripts, and are more inclined to choose texts that are virtually ready to print.
3) Most submissions require you to give a word count, and you're not yet in a position to do that. There's nothing to stop you winging it, of course, except perhaps integrity; but there's a good chance it would come and bite you on the a**.
4) Submitting when (admittedly) incomplete is likely to mark you as either a confident professional or an enthusiastic but ultimately hapless amateur. In either case, their reading your first page or two will confirm their suspicions one way or the other.
5) It's common practice - at various stages of progress but especially when you've finished - to put a work aside for a few weeks to 'mature'. On revisiting, many writers find themselves embarrassed (that's the mildest reaction I've experienced) by some of the stuff they've written in the name of art. The 'perfection' I spoke of in 2), or lack thereof, is most likely to show itself at this stage, and by giving yourself that little bit of extra time you will end up with a better result. Only the best finished product, according to your own standards and judgement, is good enough.
Why am I so black and white about this? Well, last year I finished my first novel, in that I'd written 'The end' and polished the whole thing, and submitted (three chapters by request in every case) to three agents. Only after three rejections, and gradually absorbing a better understanding of the critical structural aspects of the novel form (helped enormously by the good citizens of this board, to whom muchas grazias) did I realise that I had jumped the gun by several months.
Did I lose anything by submitting too early? Well, I've possibly burnt my bridges with three agents, the ones I most wanted to score, and there are a limited number of them here in Oz. But what I've lost most is a certain amount of self-respect, for letting a vain desire to impress override the mature reflection I'd prefer to think marks my character.
P.S. You might also want to consider getting feedback from some suitably qualified beta readers before you submit.
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Added to reflect your later post....
You should've said you'd already had qualified opinion! What I've said above remains generally true, but if your friends are being honest rather than friends you're in great shape. Go for it!