I went to the last two at Heathrow and I also throughly recommend them, I would also say that the lectures are the most valuable source of information of the whole exhibition bar none.
The guys from PPRuNe were pretty encouraging about starting out those starting out in their early thirties.
P.S. Should you attend the next one at Heathrow I recommend going by coach e.g. FlightLink. Alot cheaper, quicker and whole lot less aggro by train and tube. Both the tube station, ok their lifts then and the bus station are virtually in the same place. To find the stands for the hotel hoppa buses, walk pass the restaurant and carry on down to the pedistrian crossing, over the road and its on the right.