Junior Gears

In my first year of cycling, I'm finally prepared to enter some races. However, when applying for my BC license, I stumbled across the Gear Restriction information:

Age on 1st Jan 2011.
YOUTH A (Under 16) 6.93 metres

YOUTH B (Under 14) 6.45 metres

YOUTH C (Under 12) 6.05 metres

YOUTH D (Under 10) 5.40 metres

YOUTH E (Under 8) 5.10 metres

NOTE:
The Gear restrictions shown are the MAXIMUM gear you are permitted to use in each
age group. Tyre width and tyre pressure will alter the distance travelled per revolution
so riders are advised to always roll out the gear prior to a competition to ensure they are
within
do not exceed the maximum distance travelled per revolution. Refer to the current BC
Rule

Gear in metres = Diameter of rear wheel in metres × π (3.14) × No of teeth
on chainring ÷ No of teeth on sprocket.

So as an Under 16, my maximum Gear is 6.93m, which equates to a 42t chainring up front and a 13t sprocket on the back.

At first I was shocked, I thought that I would be spinning at like 2000rpm, but after a few days, I reckoned that it would probably be for the best.

I have a compact chainset (50/34 and 12-25) now, and for a few weeks I've only been using the little ring to practice keeping within the Ratios.

One option was to limit off four sprockets to keep within the restrictions, but I want the full range, so I've ordered a Tiagra cassette with 13 - 26, but the Chainring has pretty much stumped me.

I know that it has to be 42t, but after that I'm lost. I'm averted to my local bike shop because all the people there are really grumpy, so I turn to the Roadcc forum for Help.

I think that it is really weird that there's no provision for junior gears from major groupset manufacturers, considering that Cycling has grown into a major Sport.

Please could I have some guidance as to which chainring to purchase.

The cassette has 8 sprockets, so it will fit in to my 2300 setup.

Thanks