Trying to remember how it was for my first Skyrim char.... I think she was 12-14 by the time she hit Whiterun (having done the tutorial, bandit mine, and the tomb with the dragon stone, plus world encounters). But I didn't hit ~45-50+ until near the end of my playthrough, about the time I got my first skill to 100 and finally got around to finishing the MQ. So it slowed down a good bit.
Of course, that character had a wide base of lower-level skills, I didn't really focus-level any of them (as you can tell by only getting a 100 in the late 40's. And that was a crafting skill.)
So if it slows down like that in FO4, I think I'll be okay with it. A few quick levels, to start establishing your build (since there's just perks now, no skillpoints) seems useful. 
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Let's see what's all in the video:
(even if they said the perks are not just boring 20/40/60/80/100 bonus, it looks like a good number of the 1st ranks are straight bonuses....)
....scrolling around in the pip-boy:
Better Criticals I (LCK 6) - 50% more crit damage
Big Leagues I (STR 2) - 20% more melee damage
Commando I (AGI 2) - 20% more automatic weapon dmg
Gun Nut II (INT 3 / ?)- can use Rank 2 gun mods
Rifleman I (PER 2) - 20% more non-auto rifle dmg
Science I (INT 6) - can use Rank 0 and 1 high-tech mods
Toughness I (END 2) - +10 damage resistance
....looking at the Perk chart:
CHR
1. Cap Collector (Better buy/sell price; ? ; ?)
2. Lady Killer (+5% dmg to female, better persuade; ? ; ?)
3. Lone Wanderer (If no companion, take 15% less dmg, +50 carry; ? ; ?)
4. Attack Dog (dog holds them down for bonus VATS hit chance; ? ; ?)
5. Animal Friend (chance to pacify animals below your level; ? ; ?)
6. Local Leader (establish supply routes between your settlements; ? )
7. Party Boy (no alcohol addiction ; ? ; ?)
8. Inspirational (companions do more damage + can't hurt you; ? ; ?)
9. Wasteland Whisperer (Animal Friend, but for monsters)
10. Intimidation (chance to pacify humans below level; if pacify, can make attack [lv23]; if pacify, you can give commands [lv50])
...presumably, the 2nd and 3rd ranks of Animal Friend and Wasteland Whisperer are similar to Intimidate.
INT
1. VANS (Path to closest quest target highlighted in VATS)
2. Medic (Stims +40% hp, Radaway -40% rads; ? ; ? ; ?)
3. Gun Nut (Rank 0 & 1 gun mods; Rank 2 gun mods ; Rank 3 gun mods; ?)
AGI
1.
2.
3. Sneak (20% harder to detect; ? ; ? ; ? ; ?)
LCK
1.
2.
3. Bloody Mess (+5% damage ; ? ; ? ; ?)