Everybody has those discrepancies on some level, when they fail to meet an ideal. It's especially hard when they have set those ideals themselves, because it's the self saying to the self: you are not good enough for me.
The way to correct this doesn't lie in meeting those ideals. Not in life, and certainly not with God. We fail miserably at meeting God's ideals - even the ones he established on our "level", which is why we needed Christ's atonement. To say we do not feel good enough to receive Christ, is like saying we do not feel sick enough to see a doctor - it's subtle, and even sounds reasonable... until we find out what the diagnosis is. By our old way of thinking, the self will say to the self "see? you are even worse than I thought!". A more helpful way of thinking would be to act according to this information, whether you "personally" (which is the old self speaking) agree with it or not. We can act against our will, and we often must. The irony is, that you have probably already perfected the necessary self-control (to "will your will"), but have only been using it in service of the old self.
This is only a half-truth. By the ideals of the self (that were ingrained by various people and experiences), you might feel you don't know yourself. But what probably happens is that much of your knowledge is either latent or suppressed under the current "regime".
The effect is that you know yourself only through a window, as though at a distance, and what would otherwise be self-knowledge you now only see as unobtainable ideals. But they're only unobtainable because they oppress, rather than inspire you - they're "out there" instead of "in here". When you learn where immaturity has a place, and where maturity fits in, those concepts will already be formed and available, but you will be able to access them as your own: integrated.