which course to choose?

Which course is better to choose for B.E?

1) Mechanical Engineering

2) Aerospace Engineering

3)Aeronautical Engineering

My passion has been space exploration and rockets and flying objects since my childhood and i hv also been following the latest things related to that.... I can say my academics are also quite good to take the

pressure of the course..

However, some of my seniors said that taking aero in B.E is not advisable and they suggested that i take Mech for UG and then take up aero in PG... The reason they say is that the job opportunities in Aerospace are limited and that the field is very narrow.. that i cant switch to any other job and would have to work at almost the same labs for the rest of my life...

so,

=> which course i have to take?

=> Is there a big difference bet. Aerospace,Aeronautical Engg. ?