with the exception of dna, you all seem to have read about 20 percent of the words in the OP, chosen at random. good job folks.
Are you using point buy system? Anyway, you are going to suffer from MAD, good str, dex, con. Int has to be 12-14 in order for you gain enough skill points for the knowledge skills
. You'll need good cha for handle animal and wis for paladin spellcasting.
In order for you to reap the benefits from the knowledge devotion, assign the skill points to: Arcana, Dungeoneering, Nature, Religion and The planes. This is because you want to hit those creatures types. Otherwise you'll need handle animal and ride skills for the mount + some prereq skills as well.
If you check the Education feat from the PGtF then you'll notice that halfling cannot take it. So the build is not legal. But you can get around it..
You can either ask your DM to houserule this or you can take a regional background: Church Acolyte from Champions of Valor p.21-23. It does not cost you anything. The benefit is that you can now take the Education feat + some bonus languages. Are you even playing in the realms?
By taking strongheart halfling you get 1 feat. Then you gain 3 feats from levels. You'll need track, Mounted Combat and Mounted Archery to fullfill prerequisites. Education is for the knowledge devotion. So basically you could progress as paladin until 5th level and meet the prereqs for the HO and WPO prcs. You can also cast one 1st level paladin spell if you have wis at least 12 and gain the coveted special mount.
Note that the prcs only let you progress the paladins special mount. So you don't get it at level 9. Also the WPO prereq states that you need either animal companion or special mount which neither of you have. Unless of course your DM house rules this to be ok. One thing to remember is that HO and WPO competence bonuses to ride do not stack.
If your DM allows flaws always
take two as dna1 also suggested. Take point blank shot and precise shot. If not then you either have to postpone taking HO or WPO until you reach 5th paladin level.
My suggestion loosely following your build:
1 Strongheart Halfling Paladin of Freedom (Point Blank Shot, Precise Shot, Track, Education) (regional background: Church Acolyte)
3 PF (Mounted Combat)
5 PF [special mount]
6 WPO (Mounted Archery)
9 HO (Knowledge Devotion)
12 HO (Ride-by Attack)
15 HO (Spirited Charge)
18 HO (Reckless Charge, Miniatures Handbook)
Cramming in fighter or ranger levels nets you feats at the cost of your mount progression. Multiclassing penalty might hit you there.
You should assign your ability scores and halfling racial adjustments. Then calculate how many skill points you have per each level and assign them so that prereqs are fulfilled. You might notice that knowledge devotion is hungry for your precious points. So you may need to concentrate on only a few knowledge skills.
The last advice is that keep your build simple but optimize well.